Exposure Information and Courses from MediaLab, Inc.

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).

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 quickly as possible when received in the laboratory. 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.

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, 1992OBJECTIVES: 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.

Newfield RS. Vargas I. Huma Z.: Eikenella corrodens infections. Case report in two adolescent females with IDDM. Diabetes Care. 19:1011-3, 1996OBJECTIVE: 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 4 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 5 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.

Exposure to contact substances, such as collagen, can activate the intrinsic pathway. The exposed collagen is the location where a complex between High Molecular Weight Kininogen (HMWK), Prekallikrein (also known as Fletcher Factor, which activates to Kallikrein), and factor XII (Hageman Factor) forms. 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.

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%.

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.

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.

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

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.

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.

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 bio-terrorist 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.

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 occupation exposure statute that must be followed as well. Your supervisor will know if this applies to you.

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.

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.

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 Storing food or drink in specimen refrigerators

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

There are approximately 800,000 to 1.4 million chronic hepatitis B carriers in the U.S. Worldwide it is estimated that there are 350 million people infected with HBV, which contributes to an estimated 620,000 deaths worldwide each year (CDC, 2008).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 (CDC "Exposure to Blood" report).

After an exposure to HIV such as by a needlestick, 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.

Five to twelve weeks after the exposure, some individuals may develop flu like illness, 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.

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.

Only you can protect yourself from bloodborne pathogens.Therefore... Always think about how to perform each task in a way that minimizes your risk of exposure to bloodborne pathogens. Ensure that you are using the proper PPE for the task.Ask your supervisor if you are unsure how to accomplish the task safely.

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.

Personal protective equipment is an essential way to protect yourself from the dangers of chemicals. You'll find on the label or MSDS 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, safety goggles and rubber or nitrile gloves (not necessarily utility gloves) are necessary parts of your personal protective equipment.

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

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.

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.

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.

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 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.

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.

PEL = 0.75 ppm Permissible Exposure Limit for an eight hour time weighted average (TWA). STEL = 2.0 ppm Short Term Exposure Limit for a 15 minute exposure. Action Level = 0.5 ppm Action Level for an eight hour time weighted average (TWA).

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.

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) 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)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.

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.

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.

Stomatocytes are erythrocytes with a slit-like central pallor. Otherwise, they resemble typical RBC's in size and shape. Unless 10% or more of the RBC's are stomatocytes, their presence is probably artifactual. Stomatocytes form at a low blood acidic pH as seen in exposure to cationic detergents, and in patients receiving phenolthiazine. Hereditary stomatocytosis has some resemblance to hereditary spherocytosis, as stomatocytes may develop into spherocytes with further metamorphosis. In hereditary stomatocytosis, mild anemia and findings of on-going hemolysis should be evident if the condition presents as a clinical problem at all.

The Mycobacterium tuberculosis organism 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.

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

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 to further reduce risk of exposure of HCWs to infectious droplet nuclei that have been expelled into the air from a patient with infectious TB disease.

Healthcare 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.