| Transport of Lipophilic Substances Many lipophilic substances, including fat-soluble vitamins, cholesterol, and triglycerides are essential for life. The body needs to be able to absorb and transport these substances. However, lipophilic substances are not water-soluble, and, since blood is aqueous, this presents a challenge. The body addresses this need by using 'carriers' which can bind or sequester lipophilic molecules to aqueous 'vehicles' and thus transport them through the aqueous environment of the blood. Small lipid-soluble hormone molecules like estrogen, testosterone or cortisone are carried through the blood by binding to carrier proteins. Cholesterol and triglycerides are carried through the body in small spherical particles which trap the lipophilic molecules in their centers. These particles have an outer shell that is polar on the surface so that the particles are soluble in the blood but they have a lipophilic core which can hold fat-soluble molecules. | View Page |
| ApoB and ApoA1 By measuring ApoB we can quantify the amount of all atherogenic or potentially atherogenic lipoproteins that carry this apolipoprotein. Although lipoprotein particles other than LDL can carry ApoB, LDL accounts for the vast majority of ApoB; therefore, it is a good index of LDL particle number. Furthermore, the other particles that can have ApoB (such as IDL and Lp(a)) are also atherogenic and so it is not problematic if they are counted along with LDL, since they also contribute to cardiovascular risk. What about ApoA1? HDL-C is known as 'good cholesterol'. The role for HDL in the body is to sequester excess cholesterol and bring it back to the liver. Since HDL can remove cholesterol and transport it back to the liver for excretion or re-utilization it is indeed good. HDL is a negative cardiovascular risk factor; as its concentration goes up, a person's cardiovascular risk decreases. A person with low cardiovascular risk would have low ApoB levels and high ApoA1 levels. If we measure both ApoB and ApoA1 and express them as a ratio of ApoB/ApoA1 we get a powerful cardiovascular risk marker. The ratio should be approximately 0.3-0.9. Patients with a higher ratio have elevated ApoB (LDL) and/or low ApoA1 (HDL) and are thus at increased risk. By combining these two markers in a ratio, we get synergy and enhanced predictive power. | View Page |
| Types of Nucleic Acid Synthesis A gene is a hereditary unit or sequence of the nucleotide bases ACGT, occupying a fixed location or locus on the chromosome. It is these genes that carry all the information for life processes.DNA is rewritten into 3 types of RNA, each with a specific task: Messenger RNA (mRNA)carries the protein message to the cytoplasm. Ribosomal RNA (rRNA) is the location of protein synthesis. Transfer RNA (tRNA) is responsible for amino acid transport.Each 3-base nucleotide sequence (codon) codes for a specific amino acid. Some amino acids have more than one codon to direct their placement; this is termed degeneracy. | View Page |
| Which of the following types of RNA is responsible for amino acid transport? | View Page |
| Pre-analytical Variables Pre-analytical variables are those that affect the specimen before the actual testing begins. Some of the pre-analytical variables to consider with molecular testing include those that are applicable to all clinical specimens but should be emphasized when discussing molecular methodologies; some of these include but are not limited to: Receipt of valid order Proper patient identification Proper venipuncture procedure for blood collection Use of correct anticoagulant Collection of correct specimen type (i.e.- plasma, serum, whole blood) Order of draw Proper storage Proper transport Procedures if there is a delay in testing and/or transport | View Page |
| Resources It is imperative to follow the individual package insert procedures when collecting and handling specimens. Reference labs provide specimen requirements as well as collection, handling and transport guidelines.The Clinical and Laboratory Standards Institute (CLSI) formerly known as NCCLS: National Committee for Clinical Laboratory Standards has published procedures for collection including those specific to molecular diagnostics. | View Page |
| Transport Many clinical laboratories utilize reference laboratories for molecular methodology testing. Transport and shipping of biological specimens must follow laws and regulations governing these types of specimens. Consult your laboratory’s accrediting agency and reference lab for specific polices and procedures. | View Page |
| Disadvantages of Molecular Testing Molecular methodologies while highly advantageous do contain limitations and certain disadvantages. These can include:Cost: Molecular methodologies are usually more expensive than standard traditional methodologies. Equipment and reagent costs could be prohibitive to some laboratories. As molecular methods become more standard, the costs could potentially decrease. Currently, laboratories that consider the cost prohibitive prefer to transport molecular specimens to a reference laboratory.Personnel requirements: Depending on laboratory accreditation requirements and testing methodologies some personnel may not be qualified to competently perform molecular testing. Laboratory space requirements: Molecular amplification methods require dedicated space that may not be available in some clinical laboratories. | View Page |
| References Burtis CA, Ashwood ER, Bruns DE, eds. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 4th ed. St. Louis, MO: Elsevier Inc; 2006.Clinical and Laboratory Standards Institute (CLSI). Collection, Transport, Preparation, and Storage of Specimens for Molecular Methods; Approved Guideline. CLSI document MM13-A. NCCLS. Wayne, PA: 2005.Clinical and Laboratory Standards Institute (CLSI). Molecular Diagnostic Methods for Infectious Diseases; Approved Guideline. Second ed. CLSI document MM3-A2. NCCLS. Wayne, PA: 2006. | View Page |
| Overview Because hereditary hemochromatosis (HH) is a disease of iron overload, a review of the basic principles of iron metabolism is helpful in understanding its pathophysiology. Iron is needed by all body cells and is crucial for oxygen transport, oxidative metabolism, and cell growth and proliferation. To serve these functions, iron must be bound to protein. Iron is potentially harmful when ionized or complexed to inorganic compounds. Iron must be present in amounts sufficient to carry out these normal functions, but not in excessive amounts which may be toxic.Two types of iron-containing compounds are normally found in the body: compounds that serve in metabolic or enzymatic functions and storage compounds. Hemoglobin, myoglobin, cytochromes and other proteins are involved in oxygen transport and utilization. Iron in hemoglobin comprises about 67% of total body iron, thus erythrocytes are rich in iron. Approximately 27% of iron is found in storage compounds. Myoglobin, other tissue iron, and transport iron comprise the remaining 6% of total body iron. (2) | View Page |
| Regulation of Iron Equilibrium Regulation of iron equilibrium occurs mainly through the process of absorption. Iron is absorbed through the mucosal cells lining the duodenum. A variety of proteins are involved in this process. Hepcidin, an antimicrobial protein primarily produced in the liver, has been recently found to be a major (negative) regulator of dietary iron absorption by disrupting cellular iron transport in the intestine. Decreased levels of hepcidin are related to increased iron absorption into the bloodstream. Hepcidin is increased in response to iron overload and inflammation. (4)Additional proteins involved in iron metabolism include transferrin (Tf), transferrin receptor (TfR), ferroportin, HFE protein, hemojuvelin, and others. Their roles in iron absorption are complex and in some instances incompletely understood.Factors affecting iron absorption include: Tissue stores, e.g., decreased stored iron is associated with a decrease in hepcidin and increase in iron absorption. Rate of hematopoietic activity, e.g., an increased rate of erythropoiesis is associated with a decrease in hepcidin and an increase in iron absorption. Oxygen concentration in tissues, e.g., hypoxia decreases hepcidin and increases iron absorption, thereby promoting increased erythopoiesis. Dietary intake, including form of iron ingested, e.g., heme iron is more readily absorbed than non-heme forms of iron. Condition of GI tract mucosal cells Intraluminal factors, e.g. intestinal motility | View Page |
| Iron Transport Once absorbed through the mucosal cells of the duodenum, iron is bound to a carrier plasma protein, transferrin (Tf), for movement to sites of utilization. Almost all iron in plasma is bound to Tf, and most Tf-bound iron is carried to the bone marrow to be incorporated into developing erythrocytes. Transferrin is normally about 20% to 40% saturated with iron. (5)Transferrin releases iron to specific transferrin receptors (TfRs) for movement into cells. Transferrin receptors are found on all cells, but are found in relatively high concentration in erythroid precursors, hepatocytes, and placental cells. When the capacity of plasma Tf to bind iron is exceeded, i.e., transferrin saturation (TS) is higher than normal, excess iron is taken up by hepatocytes and other cells. A brief summary of iron metabolism is illustrated. | View Page |
| What is the protein that carries iron in the blood plasma? | View Page |
| How is the function of HFE protein altered in the C282Y mutation? | View Page |
| Match the characteristics with the cells. | View Page |
| Which of the following statements best describes a normal erythrocyte? | View Page |
| Function and Kinetics Erythrocytes are produced in the bone marrow and released into the peripheral blood where they may remain for approximately 120 days before senescence.Their main function is the transport of the respiratory gases (oxygen and carbon dioxide) between the lungs and body tissues.Each erythrocyte can be thought of as an "envelope" containing hemoglobin.Each hemoglobin molecule contains iron which has a high affinity for oxygen.As a result, when an erythrocyte passes through one of the capillaries of the lungs, it picks up oxygen.The oxygen is transported through the blood to the tissues where it is released.Carbon dioxide from the tissues then diffuses into the RBC where it undergoes chemical changes.About 70% of the altered carbon dioxide diffuses into the plasma, 25% binds to the hemoglobin molecule, and 5% goes into simple solution within the red cell.In each of these three ways carbon dioxide is transported from the body tissues back to the lungs, where it is released.
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| All of the following methods can be used to transport carbon dioxide to the lungs EXCEPT: | View Page |
| Erythrocytes or Red Blood Cells (RBC's) The first group is composed of erythrocytes or red blood cells (RBC's). The main function of the erythrocytes is the transport of oxygen from the lungs to the body tissues. Most of the cells in this Wright's stained peripheral blood smear are red cells. On is shown at the arrowhead. | View Page |
| Glossary of Terms A through M. Antibody - A modified type of serum globulin synthesized by lymphoid tissue in response to antigenic stimulus. By virtue of specific combining sites each antibody reacts with only one antigen. Anucleate - Having no nucleus. Azurophilic granules - The well-defined large reddish granules (lysosomes) which may be present in large lymphocytes. They are called "azurophilic granules" because they stain blue with the azure stains which were originally used. Basophilic granules - Specific granules present in the cytoplasm of basophils. These granules are large and stain purple-black due to their strong affinity for basic stain. B-cell - Bone marrow derived lymphocytes which produce humoral antibodies. Biconcave - Having two concave surfaces. Cellular Immunity - The capacity of a small proportion of lymphoid population to exhibit response to a specific antigen. Chromomere - The centrally located granular portion of the platelet. Clone - A population of cells descended from a single cell. Delayed Hypersensitivity - (part of cellular immunity) that develops slowly over a period of 24-72 hours after an antigenic stimulus. It consists of an accumulation of cells around small vessels and/or nerves. Example: Tuberculin skin test reaction. Digestive Enzyme - A substance that catalyzes or accelerates the process of digestion. Eosinophilic Granules - Specific granules present in the cytoplasm of eosinophils. These granules are large, refractile spheres which stain reddish-orange due to their strong affinity for acid stain. Erythrocyte (red blood cell, RBC) - One of the elements found in peripheral blood. Normally the mature form is a non-nucleated, circular, biconcave disk adapted to transport respiratory gases. Fixed Macrophage - A phagocyte that is non-motile. Free Macrophage - An ameboid phagocyte present at the site of inflammation. Graft Rejection - A transplanted tissue that is rejected by the body's antibodies. Graft vs. Host Reaction - A complication that occurs when an implanted piece of tissue, which contains antibodies, rejects the host's tissue. Granulocyte - A leukocyte which contains granules in its cytoplasm, i.e., neutrophilic, eosinophilic, or basophilic granules. Half-life - is the length of time it takes for half of the cells circulating at a given time to leave the blood for the tissues. Hemocyte - Any blood cell or formed element of the blood. Hemostasis - A mechanism of the vascular system to arrest an escape of blood. It involves an interaction between blood vessels, platelets, and coagulation. Heparin - A mucopolysaccharide acid which, when present in sufficient amounts, functions as an anticoagulant by inhibiting thrombin. Histamine - A powerful dilator of capillaries and a stimulator of gastric secretions. Humoral Immunity - Acquired immunity produced after response to an antigenic stimulus in which B cells produce circulating antibodies. Hyalomere - the clear, blue non-granular zone surrounding the chromomere of a platelet. Immune Response - The interaction of a cell and an antigen that results in a proliferation of the cell and a capacity to produce antibodies. Isotonic Fluid - A fluid whose elements have an equal osmotic pressure. Leukocyte (white blood cell, WBC) - One of the formed elements of the blood; involved primarily with the body's defense. Lysosome - A microscopic body within cell cytoplasm; contains various enzymes, mainly hydrolytic, which are released upon injury to the cell. Megakaryocyte - A giant cell of the bone marrow from which platelets are derived. Mononuclear - A cell having a single nucleus. | View Page |
| Who Must Receive Training? According to federal and international regulations, all personnel who are involved in the packaging and shipping of infectious materials are required to have training in these procedures. This includes anyone who: Packages, labels, and/or marks the package Is responsible for classifying the materials Is responsible for documenting the package contents on a shipping declaration form, air waybill, etc. Transports hazardous materials by vehicle, plane, or vessel | View Page |
| Categories of Division 6.2 Infectious Substances Hazardous material classifications are consistent across all agencies who regulate commercial shipping and are based on criteria developed by the United Nations (UN) Committee of Experts working with the World Health Organization (WHO), the Centers for Disease Control and Prevention (CDC), medical professionals, microbiologists, transportation professionals, and packaging technical experts. These requirements can be found in the 13th and 14th editions of the United Nations Recommendations for the Transport of Dangerous Goods, the 2005 - 2006 edition of the International Civil Aviation Organization Technical Instructions for the Safe Transport of Dangerous Goods by Air (ICAO Technical Instructions), and the International Maritime Organization (IMO) Dangerous Goods Code. The classification system for Division 6.2 Infectious Substances includes two catergories, known simply as Category A and Category B. | View Page |
| Definitions Before further discussion of Category A and Category B, it is important to define two additional terms that are used in the classification process. CultureAn infectious substance containing a pathogen that is intentionally propagated, for example a bacterium grown on bacteriological medium as seen in the image below. Culture does not include a human or animal patient specimen.Patient specimenHuman or animal materials collected directly from humans or animals and transported for research, diagnosis, investigational acitivities, or disease treatment or prevention. Patient specimen includes excreta, secreta, blood and its components, tissue and tissue swabs, body parts, and specimens in transport media (e.g., transwabs, culture media, and blood culture bottles).* *It is important to note that this means specimens that have been collected into these transport media, but have not yet been incubated and are not actively growing in the media. | View Page |
| Selecting the Shipping Container Manufactured packaging Follow the manufacturer's instructions if you are using manufactured packaging. Maintain copies of packaging instructions for at least one year. Outer packaging that is used to ship Category A substances must meet manufacturing and performance specifications set by the United Nations. Packaging that meets these specifications are marked by a "UN" in a circle, a series of letters and numbers that indicate the type of package, class of goods the package is designed to carry, manufacturing date, authorizing agency, and the manufacturer. An example is shown below. This packaging is available from commercial sources with preprinted UN information. The strict, outer packaging regulations do not apply to Category B packages.Reusing a containerIf you will be reusing a container, remove all irrelevant labels and markings. Use durable labels of the proper size; letters and numbers must be at least 6 mm high. Affix hazard labels securely to one side of the package, adjacent to relevant markings. Do not overlap labels. A package can be re-used if there was no leakage during the previous transport. | View Page |
| Shipper's Declaration For Dangerous Goods- Second Section In this section, options are given in the box "Transport details" for "Passenger and cargo aircraft" , or "Cargo aircraft only". You must delete the one that is not applicable. To the right of this box is an area for Shipment type, "non-radioactive," or "radioactive." Again, you must delete the one that is not applicable. This is demonstrated below. | View Page |
| 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. | View Page |
| Security Plan for Category A Infectious Substances Each facility that stores and transports hazardous materials must have a written, detailed security plan. The Select Agents and Toxins Security Information Document that was prepared by the Centers for Disease Control and Prevention (CDC) and the U.S. Department of Agriculture, Animal and Plant Health Inspection Service (APHIS) is an excellent resource to use for developing a security plan that would apply to category A infectious substances. This document can be found at http://www.selectagents.gov/resources%5CSecurity%20Information%20Document.pdfThe current version, dated March 8, 2007, is available in this course as a resource. However, because the document does undergo revisions, it is recommended that the URL given above be checked periodically for document updates. | View Page |
| References International Civil Aviation Organization. Technical instructions for the safe transport of dangerous goods by air. Doc 9284; 2005 - 2006 ed with amendment. National Laboratory Training Network. Packaging and shipping Division 6.2 materials. Georgia Public Health Laboratory; 2008. Sentinel Laboratory Guidelines for Suspected Agents of Bioterrorism. Available at: http://www.asm.org/ASM/files/LeftMarginHeaderList/DOWNLOADFILENAME/000000001202/Packing&Shipping11-18-05.pdf Accessed on February 13, 2009.US Department of Transportation Pipeline and Hazardous Materials Safety Administration. Transporting Infectious Substances Safely. Guide to changes effective October 1, 2006. Washington, DC; 2006. | View Page |
| Proper Patient Identification In order to prevent errors that affect specimen quality, the phlebotomist must pay close attention to detail during the entire venipuncture process. All steps of the phlebotomy procedure must be included for every venipuncture. This will help to maintain specimen integrity during the collection, transport, and handling of blood specimensProperly identify the patient every timeThe phlebotomist is responsible for correctly identifying the patient using two unique patient identifiers that include the patient's complete first and last name, medical record or hospital number, and/or date of birth. The patient location or room number, bed tag and chart are not reliable forms of identification and should not be used for patient identification. Every patient must verbalize his/her name to the phlebotomist, if able to do so. It is unacceptable for the phlebotomist to ask the patient to confirm his/her name that was verbalized by the phlebotomist. For example, the phlebotomist should say, "Would you please tell me (or spell) your name and birthdate. " The phlebotomist should NOT say, "Are you Sally Brown, and is your birthdate June 1, 1925?" If this is a hospital inpatient, check the information on the patient's wristband and confirm that the name and hospital number or medical record number matches the patient information on the test order. Never rely on identification attached to a bed, chart or door. NEVER draw a patient whose identity is not established or is in conflict. If there is a discrepancy, the phlebotomist must STOP and seek assistance to have the discrepancy resolved before proceeding with the venipuncture. If this is an outpatient that does not have a wristband, ask the patient (or guardian/caregiver) to state the patient's date of birth. A picture ID, such as a driver's license, can also be used for positive patient identification. | View Page |
| References Clinical and Laboratory Standards Institute (CLSI). Collection, Transport, and Processing of Blood Specimens for Testing Plasma-Based Coagulation Assays; Approved Guideline. Fourth ed. CLSI document H21-A4. NCCLS. Wayne, PA: 2003.Clinical and Laboratory Standards Institute (CLSI). Procedures for the Collection of Diagnostic Blood Specimens by Venipuncture; Approved Standard. Sixth ed. CLSI document H3-A6. NCCLS. Wayne, PA: 2007.Clinical and Laboratory Standards Institute (CLSI). Procedures for the Handling and Processing of Blood Specimens; Approved Guideline. Third Edition. CLSI document H18-A3. NCCLS. Wayne, PA: 2004.Ernst DJ. Applied Phlebotomy. Baltimore, MD: Lippincott Williams & Wilkins: 2005.Lowe B. Reinforcing safety sticklers. Advance for Medical Laboratory Professionals. May 2004; 16:2A-3A.The Joint Commission. Patient Safety-2009 National Patient Safety Goals. Available at: http://www.jointcommission.org/PatientSafety/NationalPatientSafetyGoals/. Accessed July 18, 2009. | View Page |
| Collection (continued) Other aspects of specimen collection that must be considered are the temperature of the specimen and the time needed to transport it to the laboratory.Ideally, the specimen should be collected in a room at the testing site.If on-site collection is not possible, the specimen should be kept at body temperature (37°C) from the time of collection until it arrives at the laboratory. This can be facilitated by holding the container close to the body, for example by carrying it in an inside pocket.Semen should arrive at the laboratory as soon as possible after collection, preferably within one hour.Lubricants should not be used for collection unless absolutely necessary as most lubricants are toxic to sperm. If lubricant must be used then non-toxic forms such as KY jelly or cooking oil should be the only options.
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| Collection Accurate semen analysis results require appropriate sample collection. Patients must receive detailed directions for proper specimen collection and transport. Directions should be in writing. Specific instructions should include: The period of abstinence prior to collection should be between 2 and 5 days.The entire specimen must be collected because the different portions have varying concentrations of spermatozoa.An appropriate collection container must be used.Each laboratory should designate an appropriate, wide mouth, collection container.Each lot of collection containers should be tested to ensure that it is non-toxic to sperm.Alternative collection containers should be discouraged because their level of toxicity is unknown.Use of condoms for collection should be discouraged particularly when the purpose of the semen analysis is to test for fertility. Some condoms are toxic to sperm. Collection in condoms often results in inaccurate results for semen volume and other parameters. | View Page |
| Which of the following statements are TRUE for semen specimen collection and transport? | View Page |
| Information to be obtained from patient At the time of semen collection the patient should provide the following information that will be reported as part of the final report:The time of collectionDays of abstinenceLocation at which specimen was collected: clinic or homeDifficulties during collection (e.g. spillage)Difficulties during transport (e.g. exposure to cold temperatures)Information on collection method (e.g. masturbation, withdrawal)Names of medications that he is takingA sample supplemental information collection form is shown below:
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