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Exposure Information and Courses from MediaLab, Inc.

These are the MediaLab courses that cover Exposure and links to relevant pages within the course.

Learn more about laboratory continuing education for medical technologists to earn CE credit for AMT, ASCP, NCA, and state license renewal and recertification. Or get information about laboratory safety and compliance courses that deliver cost-effective OSHA safety training and continuing education to your laboratory's employees.



Antibody Detection and Identification
Naturally Occurring Antibodies

Antibodies are immunoglobulin proteins secreted by B-lymphocytes after stimulation by a specific antigen. The antibody formed binds to the specific antigen in order to mark the antigen for destruction.The type of antigenic exposure occurring in the body determines if the antibody is a naturally occurring or immune antibody.Naturally occurring antibodies can be formed after exposure to environmental agents that are similar to red cell antigens, such as bacteria, dust or pollen. Sensitization through previous transfusions, pregnancy or injections is not necessary. These antibodies are usually IgM and react best at room temperature or lower. Most of these antibodies are not clinically significant with the exception of ABO antibodies. Examples of naturally occurring antibodies include anti-A, anti-B, anti-Cw, anti-M, and antibodies in the Lewis and P system.

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Immune Antibodies

Immune antibodies occur in the serum of individuals who become sensitized to foreign antigens through pregnancy or transfusion. IgM predominates in the primary response, IgG in the secondary response. Most react at 37°C and are considered clinically significant. Examples include antibodies in the Kell, Rh, Duffy, and Kidd systems. Immune antibodies can be classified as alloantibodies or autoantibodies.Alloantibodies Produced by exposure to foreign red cell antigens which are non-self antigens but are of the same species. They react only with allogenic cells. Exposure occurs through pregnancy or transfusion. Examples include anti-K and anti-E. Autoantibodies Produced in an autoimmune process and directed against one's own red cell antigens. React with patient's own cells and all cells tested. Can possibly mask the presence of other significant antibodies. It is very important to make sure that no underlying significant antibodies are present if an autoantibody is suspected. A positive direct antiglobulin test (DAT) or auto control could indicate the presence of an autoantibody. Examples include cold auto (P or I) or warm auto (Rh specificity).

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Naturally occurring antibodies found in the ABO blood group system may be due to exposure to which of the following?View Page

Antinuclear Antibody Testing: Methods and Pattern Interpretation
Autoimmune Disease (continued)

Why our immune system malfunctions is not completely understood. One current hypothesis is that the following series of events occurs resulting in the initiation of an autoimmune reaction. Gender and Genetic PredispositionA predisposition is usually the first step toward the development of an autoimmune reaction. Women are more likely to develop a systemic autoimmune disease than men. For example in SLE the female to male ratio is 9:1. The genotype of some individuals predetermines that their immune system will be more prone to a break in tolerance. This genetic susceptibility appears to be linked to multiple genes rather than a single gene. This is supported by evidence that some autoimmune diseases are more frequently encountered in certain ethnic groups compared to others. For example in American women between the ages of 15 and 64, the prevalence of SLE is 1 in 700 for Caucasians while it is 1 in 245 for African-American women.(Ref1) Evidence in one recent study suggests that the genes that impart an increased resistance to malaria unfortunately produce an increased susceptibility to the systemic autoimmune rheumatic diseases.(Ref2)Triggering eventThe second step is the occurrence of a triggering event that leads to a break in tolerance. For some very susceptible individuals this event might be exposure to an environmental trigger. These environmental triggers could be ubiquitous such as exposure to the Epstein Barr virus (EBV), or very limited, such as the exposure to leaking silicon from a breast implant. In others, the triggering event might be a change in hormonal balance. Whatever the case, the triggering event initiates the break in tolerance and the cascade of immunological events that eventually lead to the formation of an autoimmune disease begins.Development of autoantibodiesThe third step is the development of autoantibodies and subsequent development of clinical symptoms. Studies have shown that this process can take 3 years or longer and unfortunately, by the time the diagnosis is made, substantial damage to the body may have already occurred.

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Which of these may contribute to the development of an autoimmune disease? (Choose all that apply)View Page

Basic Tissue Orientation and Paraffin Embedding Technique
Paraffin Temperatures

Paraffin temperatures should be maintained within 2° C to 4° C of the melting point of the paraffin. The measure and control of the temperature that the paraffin media is exposed to during its use should be recorded in the quality control records. The consistent maintenance of temperatures in a controlled range will provide the best results and performance from any paraffin formula selected; since at both on the low and high end of the recommended temperature range, problems can occur. Sectioning of blocks will be easier if the paraffin is cooled at a consistent rate for even solidification of the molten paraffin into its final crystalline structure. Controlled cooling allows the formation of a uniform and homogenous matrix of crystals. Paraffin which cools too rapidly or unevenly can cause grainy textures which interfere with sectioning and may result in artifacts in the final tissue sections. On the other hand, overheating of the paraffin can result in deterioration of the components of the paraffin mixture, and some tissue specimens may become brittle or hardened by prolonged exposure to too hot paraffin.Some technical problems, which are assumed to be microtomy issues, are really problems with media selection or embedding technique, so it is worth the time to investigate.

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A final microscopic slide shows a tissue section with an incomplete outline that is not representative of the submitted specimen. What is one of the MOST likely causes of incomplete sections that occurs during embedding?View Page

Blood Banking Question Bank - Review Mode (no CE)
Which of the following activities will put an employee at risk for exposure to a Bloodborne Pathogen (BBP)?View Page
All of the following are benefits of autologous donation except:View Page
Which of the following statements best describes Rh antibodies:View Page

Cardiac Biomarkers
Atherosclerosis

Atherosclerosis is one of the leading causes of heart disease and its presence is an important risk factor for events leading to acute myocardial infarction (AMI). In the past, atherosclerosis was described as a cholesterol and lipid storage event. Now we know it is a chronic inflammatory disorder of the arterial vessels with lipid components. Atherosclerosis begins with damage to the cells that line the blood vessels. Some possible causes of this cell injury are bacterial infection, hyperlipidemia, hypertension, glycosylated products of diabetes, cytokines from adipose tissue, or exposure to toxins such as pollution and second-hand smoke. Monocytes and lymphocytes adhere to the injured site; macrophages enter and ingest proteins and, along with modified lipoproteins, create foam cells. An inflammatory milieu results as cytokines and other inflammatory molecules become involved; foam cells and white blood cells begin secreting cytokines and metalloproteinases. Myeloperoxidase is also released by degranulated white blood cells and macrophages. As inflammation and accumulation of these products continues, fatty dots and streaks are formed on the vessel lining and the formation of plaque begins. As the atherosclerotic process continues, involved cells proliferate forming a complex extracellular matrix and a fibrous cap. If development continues, possibly over decades, the plaque formations are distributed throughout various vessels, become calcified or collagenized and make the vessel walls rigid. The risk to patients with significant atherosclerosis is that eventually a narrowing of the artery (stenosis) can cause a reduction in oxygen delivery to tissues and plaque rupture can lead to an acute coronary event.

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Case Studies in Clinical Microbiology
What is the most important modifiable risk factor for enteric colonization with vancomycin-resistant Enterococcus faecium (VREF)?View Page
Review 2

Hershow RC. Khayr WF. Smith NL.: A comparison of clinical virulence of nosocomially acquired methicillin-resistant and methicillin-sensitive Staphylococcus aureus infections in a university hospital (University of Illinois at Chicago). Infection Control & Hospital Epidemiology. 13(10):587-93, 1992 OBJECTIVES: To compare the clinical virulence of nosocomially acquired methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive S. aureus (MSSA) infections in 1989. DESIGN: A retrospective comparison of host factors, in-hospital exposures, sites of infections, and outcomes of patients with nosocomial MRSA and MSSA infections. PARTICIPANTS: Forty-four adult patients with nosocomial S.aureus infections. RESULTS: The 22 MRSA-infected and 22 MSSA-infected persons were similar regarding mean age, gender, underlying diseases, and exposure to surgery. Before developing infection, MRSA-infected persons were more likely to have received antibiotics and to have stayed in the hospital > 2 weeks. Bacteremia was the most common presentation in the MRSA and MSSA groups (55% and 59%, respectively). Infectious complications and death were infrequent in both groups. CONCLUSIONS: MRSA and MSSA strains infect patients with similar demographic features and underlying diseases, but MRSA infections are significantly more common among patients with previous antibiotic therapy and a prolonged preinfection hospital stay. Clinical presentations and outcomes did not differ significantly between the 2 groups. Thus, similar to studies in the early 1980s, our findings do not suggest greater intrinsic virulence of MRSA.

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Which of the following result in most Eikenella cellulitis infections?View Page
Review 1

Newfield RS. Vargas I. Huma Z.: Eikenella corrodens infections. Case report in two adolescent females with IDDM. Diabetes Care. 19:1011-3, 1996 OBJECTIVE: To alert physicians caring for patients with diabetes to the microorganism Eikenella corrodens and to discuss the appropriate preventive and therapeutic measures to take against this potentially morbid opportunistic gram-negative bacilli. CASES: We present two cases of extra-oral E. corrodens infections in adolescent females with IDDM. The first patient had diabetes of four years' duration, which was moderately well controlled. Chronic finger biting resulted in a complex felon that evolved gradually and worsened while the patient received cephalexin orally. Delay in seeking further intervention resulted in necrosis of her distal fingertip and nail bed. The second patient had poorly controlled diabetes for five years. She developed an acute thigh abscess at an insulin injection site that resolved after drainage and intravenous antibiotics. CONCLUSIONS: E. corrodens commonly inhabits the human oral cavity and becomes a pathogen mostly when host defenses are impaired, causing abscesses and infections that are at times fatal. Patients with IDDM are compromised hosts and with daily microtrauma to their skin via glucose monitoring and insulin injections, are prone to develop E. corrodens infections that can be introduced through oral secretions by licking or biting their skin. Educational efforts aimed at preventing exposure of traumatized skin to oral secretions can minimize the risk of E. corrodens infections in compromised hosts. Early intravenous administration of antibiotics, bearing in mind E. corrodens resistance to clindamycin, metronidazole, and other antibiotics, coupled with prompt surgical intervention, is essential in successfully managing E. corrodens infections.

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Chemical Screening of Urine by Reagent Strip
Urine Specimen Processing and Transportation

In order to ensure proper stability of the specimen and accurate test results, there are guidelines in place to aid in the appropriate urine processing and transportation. These guidelines include: Ensuring that all urine collection and/or transport containers should be clean and free of debris or interfering substances.Ensuring that the collection and/or transport container has a secure lid and is leak resistant. Leak-resistant containers reduce specimen loss and healthcare worker exposure to the specimen while also protecting the specimen from contaminants.Utilizing urine containers that are made of break-resistant plastic instead of glass.Utilizing urine containers that do not leach interfering substances into the specimen.Utilizing collection containers and/or transport tubes which will not leak within the pneumatic tube system (if one is used within the laboratory facility). A leak-proof device in this situation is paramount.Proper labeling and correct identification should be applied to the collection container or tubes. This includes noting the time the specimen was collected. Remember that urinalysis specimens must be analyzed within 2 hours of collection.Ensuring that there is sufficient volume to fill the tubes and/or perform the test.

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Clinical Significance of Urine Protein (continued)

Individuals with diabetes mellitus may excrete small amounts of albumin in the urine (microalbumin) which may signal the beginning of reduced glomerular filtration. Stabilizing the blood glucose level at this time may delay progression of diabetic nephropathy. Both type I and type II diabetes mellitus are leading causes of renal failure. Microvascular damage caused by excessive renal exposure to glucose can lead to diabetic nephropathy. By the time the urine protein level reaches the 30 mg/dL level that is necessary for detection by routine reagent strips, damage to the kidneys may have already occurred. Reagent strips are available that use a dye-binding technique rather than the traditional protein-error of indicators principle. These strips are more sensitive and specific for albumin, detecting levels as low as 8 mg/dL.Women in the last month of pregnancy may develop proteinuria as the first sign of impending eclampsia. Eclampsia is the gravest form of toxemia of pregnancy. The presence of protein in this situation must be evaluated by the physician in conjunction with other clinical symptoms.Benign transient proteinuria may be the result of: exposure to cold, strenuous exercise, dehydration, and/or high fever. Benign transient proteinuria may also occur during the acute phase of a severe illness. Patients over the age of 60 have a greater chance of having protein in their urine. Occult malignancies and glomerulonephritis, that occur more frequently in the elderly, may be signaled by the presence of proteinuria. Orthostatic proteinuria is a condition seen most often in young adults. The condition may be caused by pressure on the renal nerve. When this condition is suspected, two urine specimens are tested. One specimen is collected upon arising in the morning, and the second is collected several hours later. When this condition is present, the first morning specimen, after the patient has been in a supine position, will be negative for protein. The second specimen, taken after the patient has been upright for several hours, would be positive for protein.

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The presence of increased levels of protein in the urine may be an early indicator of which of the following conditions?View Page

Chemical Screening of Urine by Reagent Strip (retired March 2012)
Clinical Significance cont'd

Individuals with diabetes mellitus may excrete small amounts of protein in the urine which may signal the beginning of reduced glomerular filtration. Stabilizing the blood glucose level at this time may delay progression of diabetic nephropathy. Women in the last month of pregnancy may develop proteinuria as the first sign of impending eclampsia. Eclampsia is the gravest form of toxemia of pregnancy. The presence of protein in this situation must be evaluated by the physician in conjunction with other clinical symptoms.Benign transient proteinuria may be the result of: exposure to cold, strenuous exercise, dehydration, and/or high fever. Benign transient proteinuria may also occur during the acute phase of a severe illness.

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Which of the following may cause false negative bilirubin results on a urine reagent strip? (Choose ALL of the correct answers)View Page
Clinical Significance

No blood is found in the urine of healthy individuals although samples from menstruating females, frequently, but not always, test positive for blood. Hematuria is associated with renal or genital urinary disorders in which the bleeding is the result of irritation to the involved organs or trauma. Examples include renal calculi, pyelonephritis, glomerulonephritis, tumors, trauma or exposure to toxic chemicals or drugs and/or strenuous exercise. Hemoglobinuria may be due to the lysis of red cells within the urinary tract. If it is caused by intravascular hemolysis, the hemoglobin is then filtered through the glomeruli. In the normal individual, the hemoglobin molecule attaches to haptoglobin and in this way bypasses the kidney filtration system. When the hemoglobin/haptoglobin system is overwhelmed, as in cases of hemolytic anemia, severe burns, transfusion reaction, infection or strenuous exercise, hemoglobin passes into the urine.

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Chemistry / Urinalysis Question Bank - Review Mode (no CE)
Which one of the following statements about lead poisoning is false:View Page

Confirmatory and Secondary Urinalysis Screening Tests
Diseases Associated with Proteinuria

Severe proteinuria (greater than 3.5 g/day) is characteristically seen in patients with glomerulonephritis, lupus nephritis, lipoid nephrosis, and severe venous congestion of the kidney. Moderate proteinuria (0.5-3.5g/day) is seen in nephrosclerosis, multiple myeloma, diabetes nephropathy, malignant hypertension, and pyelonephritis with hypertension. Mild proteinuria (less than 0.5 g/day) may be seen with polycystic kidneys, chronic pyelonephritis, benign orthostatic proteinuria, and some renal tubular diseases. Transient proteinuria can also be due to physiologic conditions such as stress, exercise, cold exposure, and fever, in the absence of renal disease.

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Limitations of the Procedure

The product profile for Ictotest® points out that bilirubin is very light sensitive, so urine specimens should be protected from excessive light exposure and examined as soon as possible after specimen collection. On standing, bilirubin, which has a goldish color, is oxidized to biliverdin, which is a green color. Many of the procedures used to detect bilirubin will not react with biliverdin, so false-negative results may occur if urine is not fresh when tested.

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Dermal Puncture and Capillary Blood Collection
Protect Yourself and Your Patient

It is important to remember that the collection of a specimen by dermal puncture may involve the potential of exposure to bloodborne pathogens as well as other safety considerations for both the phlebotomist and the patient. Some important safety reminders are listed in the table below. Safety Reminder Reason Comment Gloves are always necessary Blood contaminates the skin during a capillary blood collection. Gloves protect the phlebotomist from potential exposure to bloodborne pathogens. Gloves must remain intact to be an effective barrier against exposure to potential pathogens. Wear additional PPE, such as lab coat or gown when appropriate or required. Safety goggles and surgical mask may be needed if there is a potential for splashes or sprays of blood. May be needed to protect the phlebotomist or may be required to protect the patient from potential infection in some cases. Safety goggles and mask should both be worn to adequately protect the eyes and mucous membranes from exposure to bloodborne pathogens if there is the potential for splashes or sprays of blood. Only have the equipment needed for this procedure at hand and additional equipment out of reach of the patient. Protects the patient from accidental injury Often, capillary procedures are performed on very young children who are curious and may grab something that could cause injury.

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Protect Me From the Light

Some specimens routinely collected for testing by using a capillary puncture are adversely affected by exposure to light. One example is a specimen collected for bilirubin testing that is obtained from a newborn. When obtaining the specimen for this testing, it is important for the phlebotomist to recognize the effect of light on the specimen. Room light or sunlight can metabolize the bilirubin in the specimen to a different compound. This will cause a falsely lower bilirubin level. A neonatal bilirubin specimen should be obtained in a dark-colored (amber) container. Alternately, a clear or white container can be immediately wrapped in aluminum foil following the blood collection, preventing the blood from exposure to light.

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A patient has an order for microhematocrit testing. Which of the following should be collected for this testing?View Page

Diabetes and the Current American Diabetes Association Guidelines
HbA1C versus Blood Glucose Measurement

Advantages of utilization of HbA1C over blood glucose measurement include: Fasting is not required Greater specimen stability Less fluctuations in day-to-day levels caused by stress and illness Disadvantages of utilization of HbA1C over blood glucose measurement include: Cost per test is higher than blood glucose. Conditions that shorten red blood cell (RBC) survival e.g., hemolytic anemia, homozygous sickle cell trait, pregnancy, or recent significant blood loss, will reduce exposure of RBCs to glucose, thereby lowering the HbA1C test value. Specimens with >10% fetal hemoglobin (HbF) may have a falsely decreased HbA1C test result. If onset of diabetes is rapid, blood glucose levels will more correctly reflect glycemia than HbA1C levels.

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First Aid
Chemical Burns of Skin

Chemical burns occur when caustic or corrosive chemicals come into contact with the skin.Act immediately, since the longer the exposure, the worse the injury.

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Fundamentals of Hemostasis
Primary Hemostasis: The Vascular System and Platelet Involvement

As discussed earlier, a break in the vessel endothelium leads to exposure of collagen and the vessel's subendothelial layer. Ruptured endothelial cells leak ADP and serotonin, the chemical triggers that induce platelet adhesion, which is the next step in the sequence of hemostatic events. Circulating platelets are drawn to the area by those liberated chemical signals and begin to physically attach themselves to the rough, damaged surfaces of the damaged vessel wall. Once platelets begin adhering to the damaged area of the vessel wall, the platelets start to change their shape and functionality through a process called platelet activation. The activated platelets undergo various changes, including the alteration of their surface receptors as they prepare to create a primary platelet plug. At this time, the platelets also release the contents of their granules through a process called platelet secretion which helps to attract more platelets to the site of injury as a positive feedback mechanism. As platelets continue to arrive and bind to the exposed collagen and basement membrane, a rudimentary barrier begins to form, as the platelets themselves serve to fill in the breached vessel wall. The process by which platelets bind to one another is referred to as platelet aggregation. Platelet aggregation is vital because it allows for a primary platelet plug to be formed. The platelet plug is the structure responsible for plugging the hole in the vessel wall, preventing further blood loss. The formation of the platelet plug signals the end of primary hemostasis, and serves to initiate upcoming processes associated with secondary hemostasis.

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Secondary Hemostasis: The Intrinsic Pathway

Exposure to contact substances, such as collagen, can activate the intrinsic pathway. The exposed collagen is the location where a complex forms between:High molecular weight kininogen (HMWK)Prekallikrein (also known as Fletcher Factor), which activates to kallikreinFactor XII (Hageman Factor) Together, this three-biochemical-complex, adhered to the collagen binding site, catalyzes the conversion of factor XII to its activated form, XIIa, thereby triggering the intrinsic pathway. The intrinsic pathway is circled in red in the image below.

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General Laboratory Question Bank - Review Mode (no CE)
What is the eight hour occupational exposure limit for a chemical called:View Page
Which one of the following statements about Hepatitis is true?View Page
What is the eight hour occupational exposure limit for a chemical called?View Page

Hematology / Hemostasis Question Bank - Review Mode (no CE)
The WBC indicated by the arrow in this illustration is exhibiting:View Page

Hemolytic Disease of the Fetus and Newborn
Immunization to D Antigen

Since anti-D produces the most severe HDFN and was once relatively common, let's begin by reviewing how anti-D is produced.Immunization to D may occur when Rh-negative individuals are exposed to the D antigen, but developing anti-D varies greatly from person to person. Some individuals produce anti-D after being exposed to a small volume of D-positive red cells (e.g., 0.1 mL). For others, a relatively large volume of D-positive cells is required. Yet other persons will never produce anti-D, regardless of exposure.

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Primary versus Secondary Response

To understand the history of HDFN due to anti-D, it is useful to review the immune response. A primary (1°) immune response is the response that occurs following the first exposure to a foreign antigen. A secondary (2°)/anamnestic immune response occurs following subsequent exposures. The main differentiating features as related to producing anti-D during pregnancy are shown in the table and figure. 1o immune response 2o immune response 1. Following the first exposure to the D antigen, a lag phase occurs in which no anti-D is produced, but activated B cells differentiate into plasma cells. The lag phase can be as short as several days, but often is longer. 1. When exposure to D occurs in subsequent pregnancies, the lag phase is short (3–7 days) due to the presence of memory B cells that quickly differentiate into antibody-secreting plasma cells. 2. Depending on the antibody detection method, it often takes 5–15 weeks before anti-D is detectable in serologic tests. 2. An increase in anti-D is usually detectable within days. 3. The amount of anti-D produced is relatively low. 3. The amount of anti-D rises to a higher level. 4. Anti-D titers decline fairly rapidly and may become undetectable. 4. Anti-D titers tend to remain higher for longer but eventually decline. 5. The first anti-D produced is mainly IgM (although small amounts of IgG are usually also produced). 5. The main type of anti-D produced is IgG (although small amounts of IgM may be produced).

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Factors That Affect Production of Anti-D

Exposure to D+ red cells: Anti-D is red cell immune. The usual route of exposure to the D antigen is during pregnancy. Fetal bleeds into the mother occur more commonly at delivery but some may occur antenatally due to small lesions in the placenta or due to placenta previa, amniocentesis, abdominal trauma, abortion, ectopic pregnancy, etc. Transfusion is a relatively rare route of exposure since Rh-negative individuals normally receive only Rh-negative donor red cells. However, Rh-negative transfusion recipients may be exposed to small volumes of D-positive red cells in Rh-positive platelet concentrates. Also, there are rare reports of fresh frozen plasma, not normally matched for Rh(D), causing anti-D production.Volume of fetal bleed: In general, the larger the fetal bleed, the more likely the mother is to produce anti-D. Approximately 1 pregnancy in 400 result in a fetomaternal hemorrhage (FMH) of 30 mL or greater. ABO incompatibility between mother and fetus: If fetal red cells are ABO incompatible with the mother, maternal anti-A or anti-B will rapidly remove fetal cells from the circulation before anti-D can be produced. This protection decreases the chance of anti-D being produced but does not eliminate it entirely.

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Mechanism of Action

When first developed in the 1960s, RhIg was believed to work by a simple clearance mechanism, i.e., by coating D-positive fetal red cells with IgG anti-D, which resulted in clearance of the sensitized cells in the spleen by macrophages with receptors for IgG.Current research shows that a simple model of antigen clearance by antibody-sensitized D-positive RBCs is not the mechanism of anti-D suppression by RhIg. More is involved at the molecular level, possibly involving a down-regulation of antigen-specific B cells and related mechanisms.Regardless, if given soon enough following exposure to D+ red cells, and in a suitable dosage, RhIg has the ability to prevent immunization to D.

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Histology Special Stains: Carbohydrates
PAS: Staining Protocol

Sample Type Required: Deparaffinized and re-hydrated tissue sections on positively charged slides. Fixative: 10% Neutral Buffered Formalin Step Reagent Time Technical Notes 1 Periodic Acid 0.5% Solution 5 Minutes 2 Distilled Water 3 Changes 3 Schiff Reagent 15 Minutes Gluteraldehyde should be avoided as a tissue fixative since it is a dialdehyde that will react with this reagent and give false-positive PAS staining. 4 Potassium Metabisulfite 0.55% Solution 1 Minute in 2 Changes While some technicians omit this reagent step in the protocol with no problems, metabisulfite rinses may be necessary to remove any excess leucofuchsin left over after exposure to the Schiff reagent. Highly chlorinated water can cause these excess molecules to nonspecifically stain other tissue elements in the section. 5 Running Tap Water Up to 10 Minutes Warm to hot running water develops the PAS stain and gives a more intense staining reaction than cold water. Expected ResultsThe following elements will show positive PAS (Rose Red) staining: Glycogen Neutral mucins Some epithelial mucins Basement membranes Fungal wallsPost Staining Procedure: Tissue sections should be rinsed well in distilled water, dehydrated with 95% and absolute alcohols, cleared, and cover-slipped.

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PAS with Diastase: Staining Protocol

Sample Type Required: Deparaffinized and re-hydrated tissue sections on positively charged slides. Fixative: 10% Neutral Buffered Formalin Step Reagent Time Technical Notes 1 Malt Diastase Solution 1 hour at 37C Solution should be preheated to 37C. Do not heat the solution above 40C as enzyme activity can destroyed at higher temperatures. Insufficient heat may cause incomplete digestion of glycogen. 2 Distilled Water 3 Changes Rinse slides gently to remove diastase. 3 Periodic Acid 0.5% Solution 5 Minutes 4 Distilled Water 3 Changes 5 Schiff Reagent 15 Minutes Gluteraldehyde should be avoided as a tissue fixative since it is a dialdehyde that will react with this reagent and give false-positive PAS staining. 6 Potassium Metabisulfite 0.55% Solution 1 Minute in 2 Changes While some technicians omit this reagent step in the protocol with no problems, metabisulfite rinses may be necessary to remove any excess leucofuchsin left over after exposure to the Schiff reagent. Highly chlorinated water can cause these excess molecules to nonspecifically stain other tissue elements in the section. 7 Running Tap Water Up to 10 Minutes Warm to hot running water develops the PAS stain and gives a more intense staining reaction than cold water. Expected Results Glycogen will be absent from tissue section The following elements will show positive PAS (Rose Red) staining Neutral Mucins Some Epithelial Mucins Basement Membranes Fungal WallsPost Staining Procedure: Tissue sections should be rinsed well in distilled water, dehydrated with 95% and absolute alcohols, cleared and cover-slipped.

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Safety Precautions for Microwave Usage

While microwave use in the laboratory is considered to be relatively safe, the following safety precautions should be taken to prevent high doses of exposure to microwaves and personal injury: Periodically inspect and clean door seals and hinges. Use a microwave leakage detector to check for microwave leakage from the door seals on a regular basis. Always handle containers with potholders or thermal mitts. Never operate the microwave without a minimum volume of microwave-absorbing material inside the container. Never heat food in a microwave oven used for laboratory procedures.

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Histology Special Stains: Connective Tissue
Safety Precautions for Microwave Usage

While microwave use in the laboratory is considered to be relatively safe, the following safety precautions should be taken to prevent high doses of exposure to microwaves and personal injury:Periodically inspect and clean door seals and hinges.Use a microwave leakage detector to check for microwave leakage from the door seals on a regular basis.Always handle containers with potholders or thermal mitts.Never operate the microwave without a minimum volume of microwave-absorbing material inside the container.Never heat food in a microwave oven used for laboratory procedures.

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What should users do to prevent high dose exposure to microwaves? (Choose the BEST response.)View Page

HIV Safety for Florida
Which of the following is not considered a potentially infectious body fluid for transmitting HIV?View Page
The type of health-care occupational exposure with the greatest risk of HIV transmission is:View Page
The follow-up to a healthcare work HIV exposure includes:View Page
A person commits a misdemeanor of the first degree by:View Page
Occupational Exposures

HIV transmission, due to occupational exposure, occurs by: Percutaneous injury, such as a needlestick or a cut with a sharp object; Contact of mucous membrane or abraded skin with HIV-infected blood or body fluids. The risk of HIV transmission after a percutaneous exposure to HIV-infected blood is 0.3%.The risk of HIV transmission after a mucous membrane exposure to HIV-infected blood is .09%.The risk of HIV transmission after contact of abraded skin with HIV-infected blood is estimated to be less than .09%.

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Potentially infectious body fluids

These substances are considered potentially infectious for an occupational exposure: blood cerebrospinal fluid synovial fluid pleural fluid peritoneal fluid pericardial fluid amniotic fluid any body fluid visibly contaminated with blood semen or vaginal fluid tissues removed during surgery.

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Risk factors associated with increased HIV infection

The risk factors that increase the risk of an exposure leading to HIV infection are: larger quantity of blood from source person, and blood from source person in terminal stage of HIV disease.

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Exposure Follow-up

The follow-up to a healthcare work HIV exposure includes: psychological counseling medical evaluation postexposure testing at baseline, 6 weeks, 12 weeks, and 6 months.

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Postexposure prophlaxis

Postexposure prophylaxis will be determined by exposure type and HIV infection status of source person. The postexposure prophylaxis determined by a qualified practitioner will balance risk of infection with toxicity of the medications.The postexposure prophylaxis must be started hours after the exposure.The postexposure prophylaxis should be re-evaluated 72 hours after exposure, particularly if additional information is available about source person.The postexposure prophylaxis may be necessary for 6 months.

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If an Exposure Occurs

Give first aid. Wash needlesticks and cuts with soap and water. Flush splashes to the nose, mouth, or skin with water. Irrigate eyes with clean water, saline, or sterile irrigants. Report exposure to supervisor.

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Match the proper first aid with the exposure type.View Page
Overview

Prevention of HIV exposure is the best line of defense to prevent occupational transmission of HIV as there is no vaccine available to develop specific immunity and the postexposure prophylaxis is toxic. Following appropriate workplace practices in the laboratory focus on preventing needlesticks or other sharps injuries and exposure of mucous membranes and abraded skin to HIV-infected blood or body fluids.

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Work practice controls

Work Practice controls specify how to perform a task. Wherever there is a risk of exposure, they forbid: smoking eating or drinking applying cosmetics or lip balm handling contact lenses mouth pipetting food and drink in specimen refrigerators

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Gloves

Gloves must be worn: when there is a reasonable chance of exposure to blood, other infectious body fluids, mucous membranes, or nonintact skin. during vascular access procedures, including phlebotomy. when handling contaminated items or surfaces.Wear only flat rings under gloves as large rings may tear gloves.Replace gloves: Between patient contacts If they are damaged or contaminated Before leaving the work area. Wash hands after removing gloves.Never wash disposable gloves.

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The following workplace practices minimize risk of HIV exposure to mucous membranes or abraded skin:View Page

Introduction to Bioterrorism
Why Biological Agents Would be Chosen as WMDs (cont.)

They can have a psychological impact.Biological WMD's could possibly have a psychological impact that will go far beyond their actual effect. The very thought of exposure to a biological agent may possibly cause many people to panic. Biological WMDs can tie up resources.Some biological agents can be a hazard for lengthy periods. The use of these agents may require tedious, time-consuming, resource-intensive decontamination and monitoring of facilities before they can be returned to service.Defense may be difficult.It is very difficult for civilian government agencies to prepare for biological terrorist incidents. While most civilian agencies have some kind of hazardous material or HAZMAT response teams; in the event of a biological terrorist incident, these teams are likely to be challenged beyond their capability in terms of human resources, and equipment.

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Why Biological Agents Would Not Be Chosen as WMDs

They are not immediate. The delayed effect, for example, the long incubation period for some agents, may detract and limit their tactful usefulness as a political statement.They are hazardous to all who come in contact.There is the possibility that the biological agents could also affect the health of the aggressor forces.They are hard to control.The dependence of prevailing winds and other weather conditions such as temperature, sunlight, and desiccation may make it difficult to control distribution of the biological agent.Potential long term effects beyond the initial attack.The persistence of some agents such as spore-forming anthrax in the environment may make an area uninhabitable to aggressor forces for long periods.Results are unpredictable.Morbidity secondary to a biological attack is unpredictable since casualties will be related to the quantity and manner of exposure plus the preventive and treatment measures available.

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Is the psychological impact of a biological attack an advantage or a disadvantage of using biological weapons?View Page
Laboratory Response - Chemical, Level 2

In addition to the responsibilities listed for Level 3, over 40 laboratories also participate in Level 2 activities. At this level, laboratory personnel are trained to detect exposure to a limited number of toxic chemical agents in human blood or urine, the analysis of cyanide and toxic metals in human samples, for example.

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Laboratory Response - Chemical, Level 1

At present, 5 laboratories participate in Level 1 activities. At this level, technical personnel are trained to detect exposure to an expanded number of chemicals in human blood and urine. This includes all Level 3 and 2 laboratory analyses, plus analyses for mustard agents, nerve agents, and other toxic chemicals.

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What if: Biological Attack

Biological attacks involve bacteria, viruses or natural toxins. The effects of toxins can be immediate but for bacteria and viruses the effects may not be apparent for weeks. A bioterrorist may attack by infecting animals, contaminating food and water, spraying bacteria or viruses into the air. In infections such as smallpox and plague, once a few individuals are infected they can further spread the disease from person to person. An attack could also come from through a building's ventilation system, the mail, or even through exposure to an infected terrorist seeking to spread disease during an infectious stage.

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Microbiology / Serology Question Bank - Review Mode (no CE)
Match the type of hepatitis with its route of transmissionView Page

Molecular Methods in Clinical Microbiology
Identification of Staphylococcus aureus with Peptide Nucleic Acid (PNA)-Fluorescence In Situ Hybridization (FISH)

Staphylococcus aureus, particularly methicillin resistant strains (MRSA), have represented a likely target for molecular development, particularly in blood cultures. As more institutions implement patient screening protocols for MRSA, replacement of routine culture methods with molecular assays has gained increasing attention.PNA-FISH assays provide for the definitive identification of Staphylococcus aureus from positive blood culture vials. Peptide nucleic acid fluorescent in-situ hybridization is a relatively straight forward procedure that does not involve amplification and has limited equipment requirements. Procedurally it is easy to perform with minimal hands on time.PNA is a synthetic imitator of a nucleic acid sequence in which the backbone is a pseudopeptide rather than a sugar. PNA behaves similarly to DNA and will bind to complementary nucleic acid strands. A PNA probe is constructed, utilizing a complementary, hybridizing sequence for a known nucleic acid target sequence. The probe is typically bound to a fluorescent protein as a means of visualizing/detecting the target. In one commercially available method, once a blood culture vial demonstrates gram-positive cocci in clusters, a drop of the blood culture broth is added to fixation solution on a slide. Heat or methanol is used to fix the smear. After fixation, probe that targets species-specific ribosomal RNA is added to the smear, which is then cover-slipped.Slides are then incubated at 55oC. Post incubation, slides are immersed in a preheated wash solution and coverslips gently removed. After incubation in the wash solution, smears are air dried; a drop of mounting medium is added and the slide is cover-slipped again.The slides are examined with a fluorescent microscope, utilizing specific filters. Green fluorescing cocci in clusters are identified as Staphylococcus aureus. This identification would be available, depending on the routine identification system utilized, potentially 24 hours earlier than the norm.A significant number of blood cultures that demonstrate gram-positive cocci in clusters yield coagulase negative staphylococci (CNS), which represent potential contaminants, rather than significant infection. What is the significance of differentiating blood cultures that contain S. aureus from those that are growing CNS in a much earlier timeframe?Studies have shown that IF the differentiation of CNS from S. aureus is effectively communicated to clinicians and pharmacy/antimicrobial stewardship teams, active assessment can occur utilizing defined exclusion criteria for those patients whose cultures yielded CNS rather than S. aureus. In scenarios where contamination rather than infection is indicated, vancomycin can be discontinued earlier, and length of hospital stay is also shortened. Reduced antibiotic exposure, reduced risk of development of resistance, and reduced cost are all potential benefits.

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Multi-drug Resistant Organisms: MRSA, VRE, and Clostridium difficile
Treatment of Clostridium difficile Infection (CDI) and C. difficile Associated Disease (CDAD)

The first step in treating patients with CDAD is to discontinue the causative agent wherever possible. The choice for initial antibiotic therapy depends on the severity of disease. Oral vancomycin or metronidazole remain the mainstays of therapy for CDI, with vancomycin reserved for patients with more severe disease and/or those who have not responded to metronidazole. Metronidazole is currently favored in guidelines from the Centers for Disease Control and Prevention (CDC) on the basis of cost and concern that oral vancomycin promotes colonization with vancomycin-resistant Enterococcus. Oral fluids (water and electrolytes) may be necessary to counteract fluid loss as a result of excessive diarrhea, which can quickly lead to dehydration. Patients with fulminant disease and toxic megacolon may require colectomy. Recurrence of CDI is becoming an increasing problem. Most recurrences happen 7-14 days after completion of therapy, suggesting relapse rather than re-infection. If a patient develops a second episode of CDI following initial successful treatment, it is recommended that if possible, the same drug be used to treat the second episode. Contributing factors to recurrent CDI include:Continuing exposure to organisms either through re-infection (via contaminated environment or poor hand hygiene) or an endogenous source, such as C. difficile spores in GI tract. An inability to mount an adequate anti-Toxin A IgM and/or IgG antibody response (i.e., poor host immune response); a likely reason why CDI affects an increasingly elderly population. Unfortunately a vicious cycle can arise whereby the initial treatment prescribed, vancomycin or metronidazole, significally disrupts normal colonic flora reducing colonization resistance and leaving the patient vulnerable to the next recurrent episode.Other treatments, including the use of probiotics or anion-exchange resins to absorb toxins, may work in some cases but none work in every case.The goal of all treatment is to reestablish normal colonic flora so as to control C. difficile (over)growth.

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Disinfection & Control of C. difficile Infection

C. difficile spores resist dessication for months and are known to persist on hard surfaces for up to five months. Spores persist even after exposure to air. Epidemic strain B1/NAP1/027 is known to hyper-sporulate, a virulence-associated characteristic of outbreak strains. Health care workers are important vectors for transmission, as they may carry the spores on their hands or clothing. Alcohol-based hand sanitizers are very effective against non-sporulating organisms but do not kill C. difficile spores or remove the organism from the hands. The CDC recommends thorough hand washing using soap and water for caregivers and family members alike.Patients with C. difficile infection (CDI) should be isolated to a single room with a bathroom or cohorted (roomed) together. Staff treating infected patients should use personal protective equipment (PPE), including at least gowns and gloves, and must wash hands after removing gloves. The use of gowns helps to prevent contamination of clothing. Surfaces should be decontaminated using a solution of 10% sodium hypochlorite (bleach), this is effective in reducing environmental contamination in hospital rooms. The CDC recommends the use of bleach for cleaning patient and staff rooms during outbreaks. Control strategies involving reinforcement of Infection control practices rather than drug restriction are more effective. These practices include:Proper education of staff members involved in care of CDI patientsBetter isolation compliance Use of glovesFrequent and thorough hand washingEnvironmental decontamination

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Mycology: Yeasts and Dimorphic Pathogens (retired 2/12/2013)
Each of the following dimorphic fungal infections have been observed in animals living in their natural environment except:View Page

OSHA Bloodborne Pathogens
About This Course

This course will provide you with basic information about bloodborne pathogens, the regulations that govern safe work practices when handling blood and other potentially infectious body fluids, and necessary precautions that must be taken to minimize your risk of exposure to these infections.

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Occupational Exposure Standard

In December of 1991, OSHA issued a standard to guard against occupational exposure to bloodborne pathogens. This standard, part 1910.1030 of the Code of Federal Regulations was published in the Federal Register.On November 27, 2001, OSHA published a compliance directive 2-2.69 that now includes the revisions to the original standard.These regulations are law!Many states have an additional occupational exposure statute that must be followed as well. Your employer should be familiar with all applicable rules and standards to reduce your risk of infection with bloodborne pathogens in the performance of your job.

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Components of the OSHA Bloodborne Pathogens Standard

The Bloodborne Pathogens Standard includes these major components: Exposure control plan Preventive measures Hepatitis B vaccination Standard precautions Methods of control Engineering and work practice controls Personal protective equipment Housekeeping Labeling What to do if an exposure incident occurs

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The Exposure Control Plan

Employers must develop and implement an exposure control plan to protect employees from exposure to bloodborne pathogens. This is a document that explains how the employer will implement the OSHA Standard. A copy of your facility's Exposure Control Plan should be available to you at all times. The Exposure Control Plan must include:An exposure determination, which lists jobs that will or may subject workers to occupational exposures.Specific measures you and your employer must take to minimize your risk of exposure.Procedures to follow if there is an exposure incident.

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Exposure Categories

There are three exposure categories :Category I are those employees who, on a day-to-day basis, will come in contact with blood or body fluids as part of their normal job. This includes medical laboratory professionals, pathologists and operating room nurses.Category II are those employees who may come in contact with blood or body fluid during the course of their normal job. This includes housekeepers, transporters, and some technicians such as EKG techs.Category III are those persons who would not normally ever come in contact with blood or body fluids and generally includes secretaries, administrators, and gardeners.Persons may move from one category to another during the course of a workday.

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Methods of Control

Methods of control are ways you can protect yourself from exposure to bloodborne pathogens by using: Proper equipment Safety features Work practice controls The next few pages will acquaint you with these ways to keep yourself safe.

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Engineering Controls

Engineering controls are devices that isolate the worker from the hazard of exposure.Examples include: Self-sheathing needles (top image on the right)Sharps disposal containers (bottom image on the right) Disposable resuscitation bags Biological safety cabinets Hand washing facilitiesProper use of engineering controls in your workplace will help protect you from bloodborne pathogens.

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Work Practice Controls

Work practice controls specify how to perform a task. Wherever there is a risk of exposure to bloodborne pathogens or other potentially infectious materials (OPIM), these restrictions apply:No smokingNo eating or drinkingNo applying cosmetics or lip balmNo handling contact lensesFood and beverages cannot be kept in refrigerators, freezers, shelves, cabinets, or countertops where blood or OPIM are present.No mouth pipetting

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What should you do if you accidentally stick your finger with a contaminated needle?View Page
How Can HBV Be Prevented?

You can avoid exposure to HBV by taking the appropriate precautions, such as: Receiving the immunization against Hepatitis B Following standard precautions Maintaining proper work practices Using proper techniques when handling materials, which may be contaminated with blood or other potentially infected materials

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What Happens After HBV Infection?

After the exposure, there is an incubation period that lasts between 45 and 180 days, with an average of 90 days. Many individuals with acute HBV will have no symptoms at all. Some will have a mild illness with loss of appetite, nausea and vomiting, and fatigue. About 30% of infected individuals will develop clinical hepatitis with jaundice (yellow discoloration of the skin and eyes) due to liver dysfunction.

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How common is HBV?

There are approximately 800,000 to 1.4 million individuals with chronic hepatitis B in the United States. Worldwide it is estimated that there are 350 million people infected with HBV, which contributes to an estimated 620,000 deaths worldwide each year.*The annual number of occupational infections has decreased 95% since hepatitis B vaccine became available in 1982, from more than 10,000 in 1983 to less than 400 in 2001.*** Reference: Hepatitis B information for health professionals. CDC website. Available at: http://www.cdc.gov/hepatitis/HBV/HBVfaq.htm#overview. Accessed October 28, 2011.**Reference: Exposure to blood: What healthcare personnel need to know. CDC website. Available at: http://www.cdc.gov/ncidod/dhqp/pdf/bbp/Exp_to_Blood.pdf. Accessed October 28, 2011.

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Spread of HBV In The Community

HBV is spread in society most often:Through shared needles used to inject drugsThrough sexual contactFrom mother to child before or during birth

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How Easily is HIV Transmitted?

After an exposure to HIV, the chance of becoming infected is usually less than 1%. However, blood and body fluid that contains high numbers of viral particles are more hazardous. Because of the extremely serious nature of HIV, it is vital to take every precaution to avoid workplace exposure.

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What Happens After HIV Infection?

Days to weeks after exposure, the patient may begin to complain of fever, headache, and fatigue. This may also be accompanied by a rash.For the first several months after the infection, the exposed individual may be HIV-antibody negative and the disease may not be detected. However, the individual is still infective and can transmit the disease during this period.The disease may remain silent in the patient for months to years, even with no treatment.When the immune system is weakened enough, the patient will develop opportunistic infections and be classified as having acquired immunodeficiency syndrome (AIDS).

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What Happens After Hepatitis C Infection?

Five to twelve weeks after the exposure, some individuals may develop flu-like symptoms, including nausea, vomiting, tiredness and loss of appetite. These may last from weeks to months.Approximately 80% of infected individuals will have no symptoms at all.

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Occupational exposure to bloodborne pathogens can be prevented by which of the following means?View Page
Which of the following bloodborne pathogens poses the greatest risk of infection to health care workers?View Page
Gloves Must be Worn...

when there is a reasonable chance of exposure to blood, other infectious body fluids, mucous membranes, or nonintact skin. during vascular access procedures, including phlebotomy. when handling contaminated items or when touching contaminated surfaces.

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Which of the following would not offer sufficient facial protection if splashes or sprays of blood or other potentially infectious materials may occur?View Page
Which of the following are considered engineering controls?View Page
Exposure Incident

Even after taking all the proper precautions there is still a small chance of an exposure incident. An Exposure incident occurs when: Blood or another potentially infectious body fluid comes into direct contact with mucous membranes or non-intact skin. Parenteral exposure means: Exposure occurring as a result of piercing the skin barrier through needlesticks, cuts, or abrasions.

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If an Exposure Occurs

If an exposure occurs, wash the affected area immediately with soap and water.Contact your supervisor immediately, regardless of the situation or the time of day.

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Avoiding Exposure

Using safe work practices will help prevent exposure to bloodborne pathogens.Always think about how to perform each task in a way that minimizes your risk.Ensure that you are using the proper engineering controls and PPE for the task.Ask your supervisor if you are unsure how to accomplish the task safely.

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OSHA Bloodborne Pathogens (retired)
About This Program

This program will provide you with basic information about bloodborne pathogens and vital precautions you must take to minimize your risk of workplace exposure to these infections.

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How can HBV be prevented?

You can avoid exposure to Hepatitis B by taking the appropriate precautions which include: Hepatitis B vaccine Standard precautions Proper work practices Personal protective equipment

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How common is HBV?

Up to 1% of the U.S. population harbors the Hepatitis B virus in their bloodstream. In 1990, workplace exposure gave rise to an estimated 8,000 cases of HBV resulting in 200 to 300 deaths from acute and chronic HBV. So occupational exposure to HBV is a serious problem.

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Spread of HBV in the community(1)

HBV is spread in the community through: Sexual contact Drug abusers sharing contaminated needles An infant's exposure to its mother's body fluids

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How easily is HIV transmitted?

After an exposure to HIV by a contaminated needle, the chance of becoming infected is usually less than 1%.However, exposures from patients with high numbers of viral particles in their blood may be more hazardous.Because of the extremely serious nature of HIV, we must take every precaution to avoid workplace exposure.

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How is HIV spread?

HIV is spread in the community and healthcare workers just like HBV.Sexual contactDrug users sharing infected needlesAn infant's exposure to its mother's body fluids

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Occupational Exposure Standard

In December of 1991, OSHA issued a standard to guard against occupational exposure to bloodborne pathogens.This standard, part 1910.1030 of the Code of Federal Regulations was published in the Federal Register.On November 27, 2001, OSHA published a compliance directive 2-2.69 that now includes the revisions to the original standard.These regulations are law!

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The relevant components

These are the relevant components of OSHA standard which are required for each facility: Facility must develop an Exposure control plan Preventive measures Hepatitis B vaccination Standard precautions Methods of control Engineering and work practice controls Personal protective equipment Housekeeping Labeling What to do if an exposure incident occurs

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The Exposure Control Plan

Employers must develop and implement an exposure control plan to protect employees from exposure to bloodborne pathogens.This is a document that explains how the employer will implement the OSHA standard.It also specifies what to do if an exposure occurs.The Exposure Control Plan must include an Exposure Determination which lists jobs that will or may subject workers to occupational exposures.

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Engineering Controls

Engineering Controls are devices which isolate the worker from the hazard of exposure.Examples: Self-sheathing needles Sharps disposal containers Disposable resuscitation bags Microbiological safety cabinets Proper use of engineering controls in your workplace will help protect you from bloodborne pathogens.

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Work Practice Controls

Work Practice controls specify how to perform a task. Wherever there is a risk of exposure, they forbid:Smoking Eating or drinking Applying cosmetics or lip balm Handling contact lenses Mouth pipetting Food and drink in specimen refrigerators

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Gloves Must be Worn

Gloves must be worn: when there is a reasonable chance of exposure to blood, other infectious body fluids, mucous membranes, or nonintact skin, during vascular access procedures, including phlebotomy, or when handling contaminated items or surfaces.

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Exposure Incident

Even after taking all the proper precautions there is still a small chance of an exposure incident.Exposure incident: Blood or another potentially infectious body fluid coming into direct contact with mucous membranes or nonintact skin.Parenteral exposure: Needle stick or being cut by a contaminated sharp.

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If an Exposure Occurs

If an exposure occurs, wash the affected area immediately with soap and water and notify your supervisor at once.

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Avoiding exposure

Only you can protect yourself from bloodborne pathogens.Therefore... Use Standard Precautions, Get your Hepatitis B Vaccine, And always think about how to perform each task in a way that minimizes your risk of exposure to bloodborne pathogens.

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OSHA Formaldehyde
Relevant OSHA Standards

1987 Haz-Com Standard (29 CFR 1910.1200) is designed to help control employee exposure to chemicals on the job. 1990 Chemical Hygiene Standard (29 CFR 1910.1450) is specifically designed to meet the needs of laboratories with large varieties of chemicals, and to require specific training for laboratory employees. 1992 Formaldehyde Standard (29-CFR 1910.1048) is designed specifically for employees who work with formaldehyde. The goal of this standard is to reduce the risk of formaldehyde overexposure by establishing safe exposure limits.

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Warning Signs

Areas where formalin may exceed exposure limits must have warning signs. Access to these areas is limited to authorized persons trained to recognize the hazards of formaldehyde.

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Respirators

Respirators usually are not needed in a pathology laboratory. However, they are required if formaldehyde exposure exceeds the action level of 0.5 ppm. Respirators, if required, must be provided to you at no cost.Some OSHA-approved respirators include:Air-purifying full-facepiece or half mask respirator equipped with a canister or cartridge approved for protection against formaldehyde. If a half mask is used, gas-proof goggles must also be worn.Self-contained breathing apparatus operated in the demand mode or pressure-demand mode.

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Respirators (continued)

Respirators acceptable for use with formaldehyde must be fit-tested for each employee. Because of the OSHA face fit requirement, employees using respirators must not have facial hair. Employees must wash their face after each respirator use to prevent skin irritation from formaldehyde exposure in areas incompletely protected by the respirator.

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Symptoms of Overexposure

Formaldehyde exposure as low as 0.1 ppm (parts per million) may cause: Skin irritation Eye irritation Airway irritation Headaches and dizziness Symptoms possibly related to formaldehyde exposure should be reported immediately to management.

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Surveillance Questionnaire

Depending on the exposure level at your workplace, you may need to complete a medical surveillance questionnaire before you begin to work with formaldehyde. This questionnaire helps determine your personal risk from exposure to formaldehyde. If your level of exposure is high enough, you may be required to complete this questionnaire annually. The questionnaire is reviewed by a licensed physician and may require a medical follow-up exam. The questionnaire and exam are given at no cost to you and remain confidential.

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How is Exposure to Formaldehyde Monitored?

A monitoring badge is attached to your lab coat collar in the "breathing zone" for a specified length of time. This badge is then sent to an outside laboratory by your supervisor to determine your level of exposure to formaldehyde.

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Permissible Limits for Formaldehyde Exposure

OSHA has set these permissible limits for formaldehyde exposure: PEL = 0.75 ppmPermissible Exposure Limit for an eight hour time weighted average (TWA).STEL = 2.0 ppmShort Term Exposure Limit for a 15 minute exposure.Action Level = 0.5 ppmAction Level for an eight hour time weighted average (TWA).

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Corrective Action

When monitoring results exceed the STEL or PEL, the employer must: Develop a written plan to reduce exposure to levels below the PEL and STEL. Provide written notice of corrective actions to employees.

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Fume Hoods and Other Controls

Engineering controls must be established to reduce formalin exposure to the lowest possible level. In most cases, chemical fume hoods or/and ventilated grossing stations serve as the primary engineering controls to reduce formaldehyde vapors. Rooms in which formalin is used may also require special direct exhaust ventilation. Formaldehyde should be dispensed or used in a chemical fume hood or other appropriately ventilated and approved work area. Check your laboratory's policies and procedures to be sure you use the engineering controls provided, as well as the required personal protective equipment.

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OSHA Formaldehyde (retired)
Relevant OSHA Standards

1987 Haz-Com Standard is designed to help control employee exposure to chemicals on the job.1990 Chemical Hygiene Standard is specifically designed to meet the needs of laboratories with large varieties of chemicals, and to require specific training for laboratory employees.1992 Formaldehyde Standard is specifically for employees that work with formaldehyde. The goal was to reduce the risk of formaldehyde overexposure by establishing safe exposure limits.

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Symptoms of Overexposure

Formaldehyde exposure as low as 0.1 ppm can cause: Skin irritation Tearing of the eyes Airway irritation Headaches and dizziness

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Surveillance Questionnaire

Depending on the exposure level at your workplace, a medical surveillance questionnaire may need to be completed by you prior to your working with formaldehyde.This questionnaire helps determine your personal risk from exposure to formaldehyde.If your level of exposure is high enough, you may be required to complete this questionnaire annually.

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Permissible Limits

PEL = 0.75 ppm (Permissible Exposure Limit for an eight hour exposure)STEL = 2.0 ppm (Short Term Exposure Limit for a 15 minute exposure)Action Level = 0.5 ppm (Action Level for an eight hour exposure)These limits ensure that you will be protected from any ill effects due to formaldehyde exposure.

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Corrective Action

When monitoring results exceed the STEL or PEL, the employer must: Develop a written plan to reduce exposure to levels below the PEL and STEL. Provide written notice of corrective actions to employees.

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Respirators (continued)

Respirators acceptable for use with formaldehyde are of the negative pressure type and must be face-fitted for each employee.Because of the OSHA face fit requirements, any employee using a respirators must not have facial hair.Wash your face after each respirator use to prevent skin irritation from exposure to formaldehyde in the areas of your face not protected by the respirator.

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Respirators

Respirators usually are not needed.However, they are required if exposure exceeds action level of 0.5 ppm.If you require respirators for your work, they will be provided at no cost to you.

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OSHA Hazard Communication and Chemical Hygiene Updated to the Globally Harmonized System
Goals of this Program

Locate potentially hazardous chemicals in your workplace. Explain how to obtain a copy of a material safety data sheet (MSDS). Explain the information included on chemical labels. Identify exposure control measures.The intent of th to recognize potentially hazardous chemicals in the workplace, be able to locate the paper copies of material safety data sheets (MSDSs) in the laboratory, or know how to obtain an electronic copy of an MSDS when needed. The goals also include able to explain the information that is included on chemical labels and choose to use engineering controls, personal protective equipment and safe work practices to avoid exposure to hazardous chemicals.

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Haz-Com

In 1987, OSHA issued a regulation to help control workplace exposure to chemicals. This regulation is called the Hazard Communication Standard, but is more commonly known as Haz-Com, or the Right-to-Know Law.

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Section Four

This section includes important first aid information that you will need if you, or someone else, comes into contact with the chemical.

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Personal Protective Equipment

Personal protective equipment is an essential way to protect yourself from the dangers of chemicals. You'll find on the label or safety data sheet (SDS) exactly what kinds of clothing, gloves, and coverings you'll need to keep yourself safe. Also, the laboratory's chemical hygiene plan will include information about necessary personal protective equipment and engineering controls that will reduce your exposure to hazardous chemicals. At a minimum, chemical safety goggles and rubber or nitrile gloves (not necessarily utility gloves) are necessary parts of your personal protective equipment.

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Monitoring

Certain chemicals in use in the laboratory, such as formaldehyde, are hazardous if your exposure to them is prolonged. The amount of the chemical to which you can be exposed before possible danger is called the threshold limit value. Monitoring badges are used from time to time to measure your exposure. These are worn in the "breathing zone" for a certain period of time--often eight hours (for long-term exposure) or fifteen minutes (for short-term exposure). Based on the results of this monitoring, additional personal safety measures, such as ventilation or face-fitted masks, may be implemented for your protection.

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Packaging and Shipping Infectious Materials
What are the Training Requirements?

The training requirements that are stated in the US Code of Federal Regulations at 49 CFR 172.704 must be met by all personnel who are involved in shipping hazardous materials in the United States and training must be completed within 90 days of employment or performance of the required hazmat function (relevant documented training from a previous employer is acceptable).These requirements include: General awareness/familiarization training Function-specific training Safety training Security awareness training (Category A substances) Safety training, must be provided by the facility where the infectious materials are packaged and must include: Emergency response information Measures to protect the employee from the hazards associated with hazardous materials to which they may be exposed in the work place, including specific measures the hazmat employer has implemented to protect employees from exposure Methods and procedures for avoiding accidents, such as the proper procedures for handling packages containing hazardous materials OSHA bloodborne pathogens training is generally sufficient to meet this requirement for packaging and shipping infectious materials.

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Category A Definition and Examples

A category A infectious substance is in a form that is capable of causing permanent disability or life-threatening or fatal disease in otherwise healthy humans or animals when exposure to it occurs. Exposure would occur if the substance were released from its protective packaging and a human or animal came into contact with it. Some examples of category A infectious substances include: Bacillus anthracis (cultures only) Brucella abortus (cultures only) Brucella melitensis (cultures only) Burkholderia mallei (cultures only) Clostridium botulinum (cultures only) Creutzfeldt-Jakob disease (CJD) brain tissue specimens Dengue virus (cultures only) Escherichia coli, verotoxigenic (cultures only) Ebola virus Francisella tularensis (cultures only) Hantaviruses causing hemorrhagic fever with renal syndrome Herpes B virus (cultures only) Human immunodeficiency virus (cultures only) Lassa virus Mycobacterium tuberculosis (cultures only) Poliovirus (cultures only) Rabies and other lyssaviruses (culture only) Shigella dysenteriae type I (cultures only) West Nile virus (cultures only) Yersinia pestis (cultures only)New and emerging pathogens should also be classified as category A until or unless additional information is received to move them to category B. For example, in 2009, shipments of Influenza A 2009 H1N1 subtype specimens were initially placed into category A until sufficient information allowed them to be moved to category B. This is not an exhaustive list. Sometimes, deciding on the classification of an infectious substance requires professional judgement and involves knowing the medical history or symptoms of the source patient or animal and/or knowing the local epidemiological conditions at the time the patient specimen or culture was obtained. If there is doubt as to whether or not a substance meets the criteria of category A, it must be treated as a category A substance for shipping.

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Category B Definition, Shipping Name, and Identification Number

A category B infectious substance is not in a form generally capable of causing permanent disability or life-threatening or fatal disease in otherwise healthy humans or animals when exposure to it occurs. The proper shipping name and Identification number is:Biological substance, Category B, UN 3373

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Security Awareness

A category A infectious substance is in a form that is capable of causing permanent disability or life-threatening or fatal disease in otherwise healthy humans or animals when exposure to it occurs. Exposure would occur if the substance were released from its protective packaging and a human or animal came into contact with it. Therefore, it is critical that a category A infectious substance does not end up in the hands of an unauthorized individual who may purposely or unknowingly release the substance from its protective packaging and endanger humans or animals. Being aware of the people that you interact with in the process of packaging and sending category A substances is vital to the safety of the transport and prevention of a health disaster. An outsider with limited access and system knowledge could constitute a threat, but be aware that insiders could also be a threat, e.g., a disgruntled employee or a person who is angry with his or her supervisor or job or the government. Anyone desiring to do harm could potentially seize the opportunity to steal a hazardous material.Follow these precautionary procedures: When you are questioned about an infectious substance that you are packaging for shipment, it is important that you know the person that is asking AND that he or she has a need to know. If you do not know the person and if you are not aware that the person needs to know about the substance that is being shipped, do not answer the questions. You could refer him or her to your supervisor. Watch for unusual behavior. Secure the package until it is picked up. Check the identification of the courier who will be picking up the package. Use an intralaboratory chain of custody procedure if the specimens are tranferred within the facility or system. Track the package once it has been sent to be sure it arrives safely. Notify the Responsible Official or federal authority if the package does not arrive at its destination.

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Parasitology Question Bank - Review Mode (no CE)
Arrange the following phases of the Chilomastix life cycle beginning with human transmission:View Page

Phlebotomy
Hemogard ™ blood collection tubes

Blood collection tubes with Hemogard ™ (BD) closure protect you from blood which might splatter when the tube is opened. The rubber stopper is recessed inside the plastic shield, preventing exposure to blood present on the stopper. You will probably be using Hemogard or other tubes having protective devices.

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Activation of safety device

Activate the safety device in use at your institution.Be sure to follow your institution's procedure for activating this device to protect yourself from needlestick exposure.

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OSHA bloodborne pathogens standard

The Occupational Health and Safety Administration (OSHA), of the federal government has mandated bloodborne pathogen training for all US workers who are at risk of exposure. The next few slides cover a few highlights of this training. You will receive complete OSHA bloodborne pathogens training before you begin work.

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Preliminary Identification of the Primary Select Agents of Bioterrorism
Agent Biosafety Level (BSL) Requirements and Laboratory Exposure Risk

These agents are dangerous, highly virulent organisms that should NEVER be manipulated on an open bench! Laboratory infections can occur and the use of a class II, or higher, biological safety cabinets (BSC) is critical when aerosols are likely. The importance of following facility specific safety protocols and standard microbiology practices at ALL times cannot be understated. Agent Biosafety Level Laboratory Exposure Risk B. anthracis BSL-2 Low Y. pestis BSL-2 Medium F. tularensis BSL-2/3 High Brucella species BSL-2/3 High Burkholderia species BSL-2/3 High

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Toxins

Toxin Comment Most Likely Means of Dissemination Primary Route of Entry General Signs and Symptoms Laboratory Testing Botulism toxin: Gram stained image of C. botulinum courtesy of CDC Produced by Clostridium botulinum Could be purified and used in a bioterrorist event to contaminate food or aerosolized to cause disease Aerosol Food contamination Inhalation Ingestion Difficulty speaking or swallowing Blurred or double vision Drooping eyelids (ptosis) Dilated pupils Dry mouth, decreased gag reflex Weakening of the reflexes (hyporeflexia) Abnormal sensations such as numbness, tingling, and progressive arm or leg weakness Flaccid paralysis Culture, anaerobic Digoxigen-labeled IgG ELISA to detect A, B, E, and F toxins Mouse Bioassay for all toxin types and to confirm DIG ELISA Ricin toxin: Extracted from Castor beans Inhibits protein synthesis Causes death approximately 72 hours after initial exposure As an aerosol Inhalation Fever Cough Chest tightness Dyspnea Cyanosis Gastroenteritis Necrosis Antibody detection in clinical specimens Clinical testing not performed unless known exposure has occurred

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Location Where Organisms Naturally Occur, Disease Produced, and Mode of Transmission, continued:

Brucella species: Brucella is distributed in nature worldwide and found in domesticated and wild animals, such as cattle, sheep, and pigs. Infection with Brucella species, known as brucellosis, is caused in humans by exposure to infected animal fluids or food products. This includes ingesting non-pasteurized dairy products, such as milk or cheese, inhaling aerosols, and skin contact with the fluids of infected animals. Brucellosis poses an increased risk of occupational exposure to laboratory, veterinary, and slaughterhouse workers. Brucella is the most commonly reported laboratory-associated bacterial infection.Burkholderia mallei and B. pseudomallei: Most Burkholderia are found in soil, but B. mallei is only found in mammals. B.mallei is the causative agent for Glanders which primarily affects animals such as donkeys, mules, and horses. Horses, the organism's natural host, are highly susceptible to infection. Human infection is rare and usually occurs in people working with infected animals or laboratory workers handling the organism. The organism is endemic in Africa, Asia, the Middle East, and Central and South America, and usually enters via the eyes, nose, mouth, abrasions or cuts in the skin, or through inhalation. B. pseudomallei is found in soil and water and can accidentally infect animals, plants, and rarely humans. It is the causative agent of melioidosis, which is endemic in areas of southeast Asia, Taiwan, and northern Australia. The organism generally enters through cuts in the skin, ingestion of contaminated water, or by inhalation of an aerosol.

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Match the organism to the disease produced outside a bioterrorism event.View Page
Category A Agents: Reasons Why They May be Used to Create Public Health Emergencies

Anthrax (B. anthracis): Inhalation of anthrax spores is virtually 100% fatal Spores can remain infectious for decadesBotulism: Most lethal toxic agent known Toxin could be used to contaminate food supplies Can be aerosolized in enclosed areasPneumonic Plague (Y. pestis): Aerosolized in large amounts Short incubation period, usually in less than three days, and invariably fatal without early and effective antimicrobial therapy Untreated, fatality rate exceeds 90% Disease is spread from direct exposure to respiratory droplets of infected humansSmallpox: Highly contagious and deliberate spread by aerosol is extremely infectious Mass panic would be createdTularemia (F. tularensis): Highly contagious and easily spread An aerosol containing as few as 25 organisms can cause infection Easily penetrates the smallest breaks in the skinViral Hemorrhagic Fever: Causes internal and external bleeding and would likely cause great panic and easily spread by direct contact with body fluids or respiratory droplets Outbreak due to bioterrorist attack could lead to mass illness and death

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Why Certain Agents are Used as Weapons of Mass Destruction (WMD)

There are many reasons why certain agents would be selected for use in bioterrorist attacks, including the:Ease of availability: Biological pathogens can be obtained from nature, hospital laboratories, and university research facilities. Difficulty to detect: Small quantities can have potentially deadly or incapacitating effects on a susceptible population. Covert use of the agent: Can be spread throughout large areas by natural convection, air, or water currents. Ease in disseminating: Pathogens can be spread through ventilation systems in buildings. Transportation facilities could become part of the dissemination system by carrying biological agents far from their initial source. Psychological impact: Biological WMD’s could possibly have a psychological impact that will go far beyond their actual effect. The very thought of exposure to a biological agent may possibly cause many people to panic. Ability to tie up resources: Some biological agents can be a hazard for lengthy periods. The use of these agents may require tedious, time-consuming, resource-intensive decontamination and monitoring of facilities before they can be returned to service. Difficulty to defend against attack: It is very difficult for civilian government agencies to prepare for biological terrorist incidents. While most civilian agencies have some kind of hazardous material or HAZMAT response teams; in the event of a biological terrorist incident, these teams are likely to be challenged beyond their capability in terms of human resources, and equipment.

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Bacteria, viruses, or toxins that are chosen as weapons of mass destruction (WMD) by bioterrorists are:Easy to acquire and spread Hard to detect and defend against Capable of causing mass panic, injury, and/or deathView Page
Considerations When Using Automated Identification Systems

It is important to consider that commercial identification systems may misidentify the bioterrorism threat agents. There is an increased risk of incorrect identification for organisms that are: Slow growing Fastidious Limited in the number of strains available in the database It is also important to note that automated systems can create aerosols, which increases the possibility of laboratory exposure to these pathogens.

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Red Cell Disorders: Peripheral Blood Clues to Nonneoplastic Conditions
Stomatocytes

Stomatocytes are erythrocytes with a slit-like central pallor, given them the appearance of "coffee beans" or "kissing lips". In three dimensions, the stomatocyte is actually the shape of a bowl, as the cell has lost its biconcave morphology due to a membrane defect. Most cases of stomatocytosis are due to alteration in permeability, leading to an increase in red cell volume. Stomatocytes form at a low blood acidic pH as seen in exposure to cationic detergents, and in patients receiving phenolthiazine or chlorpromazine. Stomatocytosis can be an inherited or acquired condition.In hereditary stomatocytosis, mild anemia and findings of on-going hemolysis may be evident if the condition presents as a clinical problem at all. Individuals who possess the Rh null phenotype have osmotically fragile red cells, which take the form of stomatocytes. Individuals with this phenotype tend to experience varying degrees of chronic hemolytic anemia. Note: Unless 10% or more of the RBC's are stomatocytes, their presence is probably artifactual.

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Rh negative female with anti-D at delivery: A case study
How Long Can RhIg Be Detected?

An issue related to reaction strength of RhIg in serologic tests is how long passive anti-D from RhIg can be detected post-injection. The half-life of IgG is 23 to 26 days. Following injection of RhIg, serologically detectable levels of anti-D peak within hours (IV injection) or days (IM injection).Although the half-life of passive anti-D from RhIg is approximately 3 weeks, it may be detectable by serologic tests for approximately 8 weeks by the indirect antiglobulin test (IAT) and up to 12 weeks or more by continuous flow analyzers used to quantify anti-D. Levels of passive anti-D will decrease over time.Immune anti-D becomes detectable later (e.g., ~4weeks after exposure to D+ red cells), and generally reaches a peak after 6–8 weeks. Levels of immune anti-D will remain constant for longer and will increase following exposure to another immunizing dose of fetal D+ cells. Depending on the many variables that can affect reaction strength (mentioned earlier), as detected serologically, passive anti-D from RhIg can be detected for about 8 weeks or longer by routine, sensitive antibody detection methods.Since RhIg is injected at about 28 weeks, it is routinely detected at delivery, which could occur well before the ~40 weeks considered to be normal gestation (37–42 weeks by the World Health Organization).

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Risk Management in the Clinical Laboratory
Occupational Safety and Health Administration (OSHA)

The Occupational Safety and Health Administration is an agency working within the United States Department of Labor. It was created in 1970 by congress under the Occupational Safety and Health Act. As the primary regulatory agency in the field of occupational safety and health, its mission is to prevent work-related injuries, illnesses, and deaths by issuing and enforcing standards for workplace safety and health. Several states have also implemented their own occupational safety and health programs. To qualify as a state plan, the state agency must promulgate regulations that are equal to or more stringent than the federal OSHA program. Some of the safety regulations brought about by OSHA that affect the laboratory are: Personal protective equipment (PPE)- primarily to prevent exposure to bloodborne pathogens. Lockout/tagout- securing energy sources in an "off" condition when performing repairs of maintenance. Hazard communications- requires developing and communicating information on hazards of chemical products used in the laboratory, such as material safety data sheets (MSDS). Bloodborne pathogens- a standard designed to prevent both employees and patients from being exposed to bloodborne pathogens.

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Introduction to the Risk Management Process

Viewing risk management as a process helps set priorities and assists in ensuring a comprehensive risk management effort. There are several different approaches to the risk management process; the approach that is proposed in this course includes these five steps: Identify and analyze loss exposure. Consider alternative risk management treatments. Select what appears to be the best risk management treatment or combination of treatments. Implement the selected treatment(s). Monitor and improve the risk management program.

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Identify and Analyze Loss Exposure

Risk management is the process by which the laboratory becomes aware of risk that can cause potential loss exposure. Loss could result from a variety of circumstances and, depending upon the circumstances, can be insignificant to catastrophic. Therefore, in addition to identifying the risk, it is also important to establish the severity of the risk by determining the probability of loss if the risk is not controlled. There are a variety of ways the laboratory can identify potential risks. The following methods are generally considered among the more effective methods. Evaluating complaints from patients and clients Reviewing incident reports Evaluating deficiencies cited by accreditation or governmental inspections (external assessments) Reviewing proficiency testing results However, it is important to be sensitive to events or trends that may alert you to risk potential. For example, although continually monitoring the number of phlebotomies that are performed in a day may not be a normally effective method for evaluating risk, if there is a sudden staff shortage of phlebotomists or a sudden increase in hospital census, it may be worth evaluating the number of phlebotomies that are done because the risk potential may increase if the phlebotomy staff is overworked.

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Errors Related to Risk Management

When the need for root cause analysis arises, it is hoped that the investigative team will be receptive to all suggestions and proposals in addition to making a systematic analysis. Listed are three mistakes that commonly afflict the risk management process and consequently can affect positive outcomes. The risk control that should be applied is exposure avoidance.Anchoring error: This term refers to the deliberative trap of allowing first impressions to exert undue influence on the risk analysis.Confirmation bias: This is a tendency to focus on evidence that supports a working hypothesis rather than looking for evidences that supports an alternative solution.Anchoring bias: This refers to the tendency to hold on to an initial solution even in the face of disconfirming evidence.

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Semen Analysis
Documenting Collection Information

Specimen collection and handling information should be recorded and included with the semen analysis report, including:The time of collectionDays of abstinenceLocation at which specimen was collected: clinic or homeCollection or transport problems (e.g., incomplete specimen, specimen exposure to cold temperatures)Method of collectionAbnormalities of liquefactionTime of specimen receipt and analysisA sample supplemental information collection form is shown below:

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The Influenza A Virus: 2009 H1N1 Subtype
About the Virus (continued)

Susceptibility to an influenza virus strain is dependent on the immune status of the human host, since our bodies become immune only to the strains that we have been exposed to previously (either naturally or by vaccination). The lack of previous exposure to this subtype resulted in the rapid spread and increased number of infections, especially in the younger population. Respiratory infections occurred, even among those individuals who had received the seasonal flu vaccine because that vaccine was not formulated to protect against the influenza A 2009 H1N1 subtype.

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Theoretical and Practical Aspects of Routine H&E Staining
Hematoxylin Oxidation

Hematoxylin is the most widely used natural dye. However, it has little natural affinity for tissues, and needs to be oxidized to encourage tissue staining. The oxidation product of hematoxylin is hematein. This conversion process is called "ripening" and can occur naturally or chemically.The natural oxidation process takes place upon exposure to air and light and can take as long as 3-4 months before ripening is complete. However, the end product retains its staining ability for a long period of time.Chemical oxidizing agents convert the hematoxylin to hematein almost instantaneously. However, the resultant solution has a shorter shelf-life.

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Transfusion Reactions
An acute hemolytic reaction may be caused by which of the following? (Choose all that apply)View Page
Pathophysiology

The exact mechanism of lung injury in transfusion-related acute lung injury (TRALI) has not be identified. It is believed that the mechanism may vary from patient to patient. The most common finding is leukocyte antibodies in donor or patient plasma. Anitbodies to human leukocyte antigen (HLA) have been associated with TRALI. These anti-HLA antibodies can be formed in response to exposure to foreign antigens from transfusion or pregnancy. The source of the antibody is usually the donor not the patient. Transfused antibodies react with the recipient which results in leukocyte emboli aggregating in the lung capillary bed. Capillary damage triggers interstitial edema and fluid in the alveolar spaces, causing decreased air exchange and hypoxia.

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Tuberculosis Awareness for Health Care Workers
Tuberculosis Infection

TB infection is usually followed by an immune response and latency after exposure. In about 5-10% of cases, the latent period progresses to an active infection.Infection occurs when a susceptible person inhales droplet nuclei containing Mycobacterium tuberculosis and the organism reaches the alveoli of the lungs. The minimal infectious inoculum may be as low as one viable organism.About 2-12 weeks after infection, the immune system limits multiplication of additional bacteria and the immunological test becomes positive.Latent tuberculosis infection (LTBI) is the stage when the viable organism remains in the body; the individual has no symptoms and is noninfectious.Most persons infected with M. tuberculosis do not experience clinical illness and are noninfectious. About 5-10% of persons who are infected and are not treated will develop active TB during their lifetime. The risk for progression is highest during the first several years after infection.Most often, M. tuberculosis infects the lungs. However, it can infect almost any organ in the body, including bones and joints. Tuberculosis meningitis is a TB infection that occurs outside the lungs with devastating consequences, most often in young children and patients with AIDS.

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How Tuberculosis is Spread

Mycobacterium tuberculosis is spread through infectious droplet nuclei. When a person infected with pulmonary tuberculosis coughs, sneezes, shouts, or sings, the infectious particles are expelled into the air. The risk of infection is related to both concentration of infectious droplet nuclei and duration of exposure. Laboratory workers are at risk when an infectious aerosol is generated while handling liquid cultures, during preparation of frozen sections, and when performing autopsies on infected patients.

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High-Risk Infection Groups

Geographic areas with high incidence of tuberculosis include Africa, Asia, eastern Europe, Latin America, and Russia. Persons at higher risk for exposure to and infection from Mycobacterium tuberculosis include: Frequent travelers to areas of the world where tuberculosis is endemicResidents and employees of high-risk congregate settings such as correctional facilities, long-term care facilities, and homeless sheltersHealth care workers who serve high-risk patients or have unprotected exposureMedically underserved and low-income populationsInfants, children, and adolescents exposed to adults in high-risk categories

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The descriptions listed below all relate to tuberculosis (TB). Match each of the descriptions with the item in the drop-down box that it describes.View Page
Tuberculosis Exposure Control Plan

The CDC recommend that all health care facilities develop a TB exposure control plan. The plan should include an exposure determination at defined intervals for all employees who may have occupational exposure to tuberculosis. Additionally, it should provide for engineering controls and work practice controls for procedures that potentially may aerosolize Mycobacterium tuberculosis, including these procedures:BronchoscopyEndotracheal intubationSuctioningOther respiratory proceduresOpen abscess irrigationSputum inductionAerosol treatments that induce coughingFor laboratory workers, procedures that are at high-risk of producing aerosols include:Handling unfixed tissues in surgical pathology or autopsiesProcessing specimens in the microbiology section from patients with suspected or confirmed tuberculosis

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Health Care Worker (HCW) Tuberculosis Screening

All HCWs receive baseline TB screening upon hire, using either the two-step skin test or blood test. Annual screening varies depending on setting risk. In low-risk settings, screening is not necessary unless an exposure occurs.In medium-risk settings, all HCWS are screened for symptoms and HCWs with negative baseline results are tested.In potential ongoing transmission settings, HCWs receive testing every 8-10 weeks until lapses are corrected.

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Match the recommended frequency for TB screening of a health care worker with the risk category of the health care setting from the drop-down box:View Page
Three Levels of TB Infection Control

Administrative controls reduce the risk of exposure to persons who might have TB disease.Environmental controls prevent the spread and reduce the concentration of infectious droplet nuclei in ambient air.Respiratory protection controls are for situations that pose a high risk of exposure. These controls further reduce risk of occupational exposure to infectious droplet nuclei.

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Respiratory Protective Equipment

Respirators are used in situations that pose a high-risk for exposure to infectious aerosols. The most commonly used respirator in the health care facility is the N95 respirator, shown in the image on the right. An N95 respirator should be used when collecting specimens from patients with known or suspected cases of active tuberculosis. In a microbiology laboratory, a respirator should be used when it is probable that aerosols might be released in the biosafety cabinet at substantial levels as a result of the manipulation of the potentially infectious specimen. Health care workers (HCW) are screened for medical conditions by a physician prior to using respiratory protection.Annual fit-testing and training on proper usage of the N95 respirator is required. Fit testing ensures a good face seal can be achieved. Each time the respirator is worn, the wearer performs a user-seal check to ensure adequate respiratory protection. HCW who, for medical reasons, cannot use N95 respirators and men with beards or other facial hair that would interfere with the seal between the face and the respirator must use a different type of respirator that offers sufficient aerosol protection but does not require fit-testing. However, annual training on proper usage is required.

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Protect Yourself

Health care workers must be alert for signs and symptoms of TB to protect themselves from inadvertent exposure.Help protect yourself, coworkers, patients, and visitors by: Having current TB screening according to the risk classification of your setting Understanding the risks of TB in your work area Practicing good infection control at work and at home

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White Cell and Platelet Disorders: Peripheral Blood Clues to Nonneoplastic Conditions
The pale-staining cytoplasmic bodies marked by the arrow in the image may be seen in each of the following conditions except:View Page


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