Labce

Which of the following antibodies causes the MOST severe cases of hemolytic disease of the fetus and newborn (HDFN)? Anti-I Anti-N Anti-A,B Anti-D

Anti-D. Feedback Anti-D is the most common cause of severe HDFN. Anti-I is not implicated in HDFN because it is IgM in nature and I antigens are not well-developed at birth. Anti-N is not usually implicated in HDFN because it is IgM. When cases of HDFN have occurred they are very mild. Anti-A,B is frequently implicated in HDFN, but the disease is generally mild, often subclinical.

Which one of the following may cause a FALSE-NEGATIVE result with antiglobulin techniques? Dust or dirt is present in the glass tubes used for antiglobulin testing. Patient or donor blood specimen was collected in silicone gel tubes. Patient or donor blood specimen has a positive DAT. Addition of AHG reagent is delayed for 40 minutes or more after final saline wash.

Addition of AHG reagent is delayed for 40 minutes or more after final saline wash. Feedback The AHG reagent must be added to the cells immediately following washing. Antibodies may elute from the cells if the cells are allowed to sit in saline without the addition of the AHG reagent. The AHG reagent can be neutralized by the presence of the antibodies now present in the saline, causing a false negative result, or too little IgG antibody remains attached to the cells for detection by the AHG reagent. False-positive reactions can result from dust or dirt in the glassware used for testing (clumping could occur that is mistaken for agglutination). False-positive reactions can result from the use of samples collected in silicone gel tubes due to complement attachment. If the patient or donor has a positive DAT, antibody coating the patient or donor RBCs can interfere with antiglobulin testing, for instance, phenotyping with antisera requiring an antiglobulin phase of testing.

All of the following have an impact on electrophoresis techniques in the clinical laboratory EXCEPT? Amount of light present in electrophoresis box Support medium pH Voltage

Amount of light present in electrophoresis box. Feedback The type of support media, type of stains used, and voltage settings all impact electrophoresis techniques; however, the amount of light present in an electrophoresis box does not. Support medium can affect the migration of analytes based on the medium's pore size and endosmosis. pH can change the charge of the analyte and thus affect mobility. It can also denature the analyte (protein). Voltage is proportional to the velocity of the analyte migration. Ionic strength, ions present, wattage, current, temperature, and time are other variables that can affect electrophoretic results.

A patient demonstrates an antibody that reacts at the immediate spin phase, shows variable dosage, and has increased reactivity after treatment with enzymes. Which antibody does the patient most likely have? Anti-M Anti-Fya Anti-e Anti-P2

Anti-P2

When should you first refer to a chemical's label? Before moving or opening the chemical Before disposing of the chemical After a spill After accidentally ingesting the chemical

Before moving or opening the chemical. Feedback The correct answer is before moving or opening the chemical. You should always read a chemical's label BEFORE working with the chemical to ensure the proper precautions are being taken. It is also in the best interest of laboratory professionals to learn as much as possible about the chemicals they work with in order to decrease the risk of improper handling, storage, usage, contamination, etc.

According to the National Fire Prevention Association (NFPA), electrical fires are classified as: Class A Class B Class C Class D

Class C. Feedback Fires that involve electricity or electrically charged equipment are designated as class C fires. Class A fire involve ordinary combustibles, class B fires involve flammable liquids and gases, and class D fires involve flammable metals.

A Gram stain of drainage from an open wound revealed gram-positive bacilli with spores. This description would commonly rule out which one of the following organisms? (Choose the BEST response.) Clostridium perfringens Bacillus cereus Clostridium septicum Bacillus anthracis

Clostridium perfringens. Feedback The presence of spores virtually rules out Clostridium perfringens. While the organism does produce spores, they are rarely seen in clinical infections. Bacillus cereus produces spores, but it does so only under aerobic and not under anaerobic conditions. Clostridium septicum produces spores as does B. anthracis. By elimination, Clostridium perfringens is the best answer.

Which of the following organisms causes Q fever? Coxiella burnetii Anaplasma spp. Orientia tsutsugamushi Rickettsia rickettsii

Coxiella burnetii. Feedback Q fever, an acute systemic infection affecting the lungs, is caused by Coxiella burnetii. Anaplasma spp. causes human granulocytic anaplasmosis. Orientia tsutsugamushi causes scrub typhus. Rickettsia rickettsii causes Rocky Mountain spotted fever.

Which of the following is true of genotype screening in pharmacogenomics? Genotype screening gives a better overall picture of drug metabolism than measuring metabolism with probe drugs. Genotyping does not take into account drug interactions which can affect metabolism. Genotyping typically involves measuring only one mutation site or polymorphism. Genotyping has no known impact on drug metabolism.

Genotyping does not take into account drug interactions which can affect metabolism. Feedback Genotyping, while more robust and definitive, cannot factor in environmental or health variables that could affect drug metabolism. Probe drug analysis does factor in these variables, but it is more complex and tedious. Genotyping typically involves measuring many polymorphisms. For example, a laboratory that offers CYP2D6 profiling may measure twelve of the most common and significant mutation sites on this enzyme.

Which of the following drugs is used to treat congestive heart failure? Disopyramide Quinidine Procainamide Digoxin

Digoxin. Feedback Digoxin is a cardioactive therapeutic drug used to treat congestive heart failure. Disopyramide, Quinidine, and Procainamide are all anti-arrhythmic medications used to treat various cardiac arrhythmias (irregular heartbeats).

Which of the following types of automated chemistry analyzers allows for each specimen and accompanying reagents to have their own space? Discrete analyzer Random access analyzer Multi-channel analyzer Parallel analyzer

Discrete analyzer. Feedback Discrete = Each specimen and accompanying reagents have their own space Random Access = Specimens can be analyzed out of sequence Parallel = All specimens analyzed at the same time Multi-channel = Each specimen may be subjected to multiple analyses

You are working to validate a new method for detecting C-reactive protein (CRP) in serum. To assess precision, you run a medium-level control 30 times and determine the mean to be 4.0 mg/dL with a standard deviation of 0.04 mg/dL. What could be said about the precision of this run, assuming a CV less than 3% is acceptable? It is not acceptable, with a coefficient of variation of 100%. It is not acceptable, with a coefficient of variation of 10%. It is acceptable, with a coefficient of variation of 0.1%. It is acceptable, with a coefficient of variation of 1%.

It is acceptable, with a coefficient of variation of 1%. Feedback It is acceptable with a coefficient of variation of 1%. Precision is often measured by extrapolating and evaluating the coefficient of variation, or CV. To find the percent CV, you must divide the standard deviation by the mean and multiply the result by 100. 0.04 mg/dL divided by 4.0 mg/dL is 0.01. Multiplied by 100 = 1%, which is well below 3%. This indicates that the precision of this particular run is acceptable according to the parameters given. NEXT QUESTION

Identify the structure at the tip of the arrow for the letter "C". Cilia Micronucleus Cytostome Macronucleus

Micronucleus. Feedback Micronucleus is correct. Letter "C" is pointing to the micronucleus of a Neobalantidium coli trophozoite. It is the only trophozoite that contains a macronucleus and a micronucleus. The micronucleus is typically next to the macronucleus of the amoeba. This parasite is the largest protozoan in terms of size and is known to infect humans. Infections with Neobalantidium coli may remain asymptomatic or develop into balantidiasis, a condition that often resembles amoebic dysentery. Cilia is incorrect. Letter "A" is pointing to the cilia. The organism moves by means of cilia; therefore, this amoeba is in the Ciliata class. Cytostome is incorrect. Letter "D" is pointing to the cytostome. The anterior end of this organism is more pointed and displays a cytostome or primitive mouth opening. This organism can be seen in wet preparations under low power. Macronucleus is incorrect. Letter "B" is pointing to the macronucleus. The macronucleus is a large, bean-shaped structure.

How is valproic acid (Depakote) administered? IM injection Sublingual Oral preparation IV

Oral preparation. Feedback The correct answer is oral preparation as the gastrointestinal tract completely and rapidly absorbs valproic acid, so other delivery methods are not as useful for therapy.

Which three hormones are known to regulate serum Ca2+ by changing their secretion rate in response to changes in ionized Ca2+? TSH, vitamin A & calcitonin T4, vitamin B12 & calcitonin PTH, vitamin D & calcitonin T3, vitamin E & calcitonin

PTH, vitamin D & calcitonin. Feedback Three hormones, PTH (parathyroid hormone), vitamin D, and calcitonin, are known to regulate serum Ca2+ by altering their secretion rate in response to changes in ionized Ca2+. PTH secretion in the blood is stimulated by a decrease in ionized Ca2+. The active form of vitamin D increases Ca2+ absorption in the intestine and enhances the effect of PTH on bone resorption. Calcitonin is secreted when the concentration of Ca2+ in blood increases. Calcitonin exerts its Ca2+-lowering effect by inhibiting the actions of both PTH and vitamin D.When TSH (thyroid-stimulating hormone) secretion increases, it increases thyroid hormone production. Vitamin A and other retinoic acids are a group of compounds essential for vision, cellular differentiation, growth, reproduction, and immune system function.T4 loses an iodine and becomes T3, the active form of thyroid hormone. Vitamin B12 (cobalamin) participates as a coenzyme in enzymatic reactions necessary for hematopoiesis and fatty acid metabolism.T3 combines with its nuclear receptor on thyroid hormone-responsive genes, leading to the production of messenger RNA, which, in turn, leads to the production of proteins that influence metabolism and development. Vitamin E is a powerful antioxidant and the primary defense against potentially harmful oxidation that cause disease and aging.

A phlebotomy instructor asks one of her students, "what is the difference between serum and plasma?" How should the student respond? They are exactly the same. Serum contains fibrinogen while plasma doesn't. Plasma contains fibrinogen and all other clotting factors while serum doesn't. They look different. Serum is darker looking.

Plasma contains fibrinogen and all other clotting factors while serum doesn't. Feedback The student should respond by saying that plasma contains fibrinogen and all other clotting factors, while serum doesn't. Plasma is the liquid portion of blood that has been collected with an anticoagulant. Common anticoagulants include heparin, sodium citrate, and EDTA. Each of these anticoagulants works in slightly different ways to prevent blood from clotting.Serum is obtained when a blood specimen has clotted. Fibrinogen and other key clotting factors get used up in the clotting process.Serum and plasma samples collected from the same patient at the same time will look very similar. In fact, one would likely not be able to tell the difference based on appearance alone.

A copper reduction method (e.g. Clinitest® or Benedict's) is performed on pediatric specimens in order to check for the presence of: Reducing substances Aspirin Protein Ketones

Reducing substances

All of the following specimen collection methods should be used if urine cultures are also required, EXCEPT? Routinely voided "Clean catch" Catheterized Suprapubic aspiration

Routinely voided. Feedback A routinely voided urine specimen is NOT acceptable for culture. An aseptic technique must be used to prevent contamination with urethral or vaginal bacteria that may cause misleading positive cultures. If the sample is to be cultured, the container must be sterile. The preferred method is the "clean catch" collection. The external genitalia is cleansed with a mild antiseptic solution. The first part of the urine stream is discarded while collecting only the midstream portion of the urine. Catheterized specimens and suprapubic aspiration specimens will also produce non-contaminated urine specimens, but they are more invasive and painful and should be used only as a last resort.

Select the primary reagent components used in the Jaffe reaction for creatinine. Alkaline copper (II) sulfate Saturated picric acid and sodium hydroxide Sodium nitroprusside and phenol Phosphotungstic acid

Saturated picric acid and sodium hydroxide. Feedback Saturated picric acid and sodium hydroxide are the main reagents used in the Jaffe reaction for creatinine determination. These chemical components usually cause the creatinine reagent to have a bright red-orange color.

Removal of which of these organs may be a last resort treatment for a patient whose platelet count is less than 30 x 109/L as a result of immune thrombocytopenia? Gall bladder Pancreas Spleen A kidney

Spleen. Feedback In immune thrombocytopenia, antibodies develop that coat the platelets. The spleen produces macrophages whose Fc receptors recognize and destroy these antibody-coated platelets. Removing the spleen would decrease platelet destruction, but it is a last resort since the immunologic function of the spleen would also be lost. Removing the gall bladder, pancreas, or a kidney would not improve immune thrombocytopenia.Splenectomy appears to be most beneficial in patients with hereditary or acquired conditions in which RBC's or platelets are undergoing increased destruction.

Which of the following is a TRUE statement when performing maintenance or repair tasks on electrical equipment? The Occupational Health and Safety Administration (OSHA) does NOT have any standards that are aimed at protecting workers from injury when performing maintenance or repair tasks on electrical equipment. It is unnecessary to take any additional measures when performing repairs on a piece of equipment, except to turn it off. Tagout is the placement of a tag on the energy-isolating device notifying staff: "Do Not Operate this Equipment." Two-prong electrical plugs are acceptable for all equipment.

Tagout is the placement of a tag on the energy-isolating device notifying staff: "Do Not Operate this Equipment." Feedback Tagout is the placement of a tag on the energy-isolating device notifying staff: "Do Not Operate this Equipment." Lockout is the physical placement of a device on the breaker or the placement of the plug into a canister to prevent its use. Extra measures are necessary to reduce the risk of shock or injury due to the unexpected startup of equipment or the release of hazardous energy while a machine or instrument is out of service. Simply turning it off is NOT sufficient. The OSHA Control of Hazardous Energy standard, 29 CFR 1910.147, requires lockout/tagout (LOTO) procedures to protect workers whenever maintenance or repair tasks are being performed on electrical equipment.Three-prong electrical plugs should be used for all equipment.

Which of the following activities may lead to a HIPAA violation lawsuit? Faxing patient health information (PHI) to the patient's physician who order the laboratory tests. Throwing laboratory test requests into the regular trash. Discussing patient information with a patient's family member with the patient's permission. Logging off the computer after entering blood collection updates.

Throwing laboratory test requests into the regular trash. Feedback Although innocent in nature, throwing laboratory test requests into the regular trash; may lead to a HIPAA violation lawsuit. The regulations do not prevent faxing of PHI. Covered entities must have appropriate policies, procedures, and processes in place to make faxing of PHI as secure as possible. Healthcare professionals should get prior permission before discussing the patient's health with family members to avoid a lawsuit. Logging off the computer after entering blood collection updates should not result in a HIPAA violation lawsuit.

All of the following are RNA nucleotides EXCEPT? Thymine Uracil Adenine Guanine

Thymine. Feedback Uracil replaces thymine in RNA Guanine is present in RNA Adenine is present in RNA

A person who lived in the United Kingdom between the years of 1980 and 1996 for 3 or more months is indefinitely deferred from donating blood or blood products based on an increased risk of which of the following? Malaria Leishmaniasis Creutzfeldt-Jakob disease (CJD) and/or variant Creutzfeldt-Jakob disease (vCJD) Chagas disease

Creutzfeldt-Jakob disease (CJD) and/or variant Creutzfeldt-Jakob disease (vCJD). Feedback The correct answer is CJD and/or vCJD. If a potential blood donor spent more than 3 months in the United Kingdom between 1980 and 1996, or 5 or more years in France from 1980 to the present, they are indefinitely deferred due to an increased risk of CJD and/or vCJD. If they have ever been diagnosed with CJD or vCJD, they are permanently deferred.Persons with malaria or who have been infected with malaria are deferred for a period of 3 years after they are asymptomatic. The United Kingdom (UK) is not a malaria-endemic area and traveling to the UK in and of itself, would not be cause for deferral based on a potential malaria infection.Traveling to an area that is endemic for Leishmaniasis may be cause for a 12-month deferral from the time you left the area. The UK is not an Leishmaniasis endemic area. It is endemic in tropical and subtropical areas of the Middle East, Mediterranean, Africa, Central and South America, and Asia.Chagas disease is endemic in parts of Central and South America and Mexico. The UK is not an endemic area of Chagas disease. All potential donors are tested one time for Trypanosoma cruzi, the causative agent of Chagas disease. If the potential donor tests nonreactive for Chagas disease, the donor doesn't need to be retested. The rational for this is that most persons with Chagas disease have a chronic infection that was acquired while in a endemic area.

A pregnant female has been injected with Rh Immune Globulin (RhIG) antenatally (28 weeks gestation) and has a positive antibody screen at delivery. The antibody has been confirmed as anti-D alone and reacts only weakly (1+ in the indirect antiglobulin test). This antibody may be the result of: Massive fetomaternal hemorrhage at delivery Passive anti-D (RhIg) received at 28 weeks. Wharton's jelly contaminating the sample Patient has an autoantibody

Passive anti-D (RhIg) received at 28 weeks. Feedback Rh Immune Globulin is administered at 28 weeks of gestation and at delivery to help prevent pregnant women from becoming actively immunized to the D antigen. RhIG is given because during pregnancy and at delivery fetal blood can enter maternal circulation. This exposure to the D antigen puts the mother at risk for becoming sensitized and making an anti-D. Women who are Rh negative carrying an Rh positive fetus now receive RhIG at 28 weeks (antenatal) and at delivery (within 72 hours of delivery) to clear fetal red blood cells from maternal circulation. The RhIG can attach to fetal red blood cells which are then cleared by macrophages. At delivery some Rh negative women have a weakly reactive anti-D still in circulation from RhIG administration at 28 weeks of gestation (antenatal). The anti-D has been demonstrated to stay in circulation 2 months or even longer in some cases. Massive fetomaternal hemorrhage may sensitize a woman but this would not be detected at delivery. Wharton's jelly would be present in the cord sample from the baby and may cause incorrect results (rouleaux) for the baby. The mother is Rh negative since she received RhIG so the anti-D present is not an autoantibody.

Why is Rh immune globulin (RhIg) administered within 72 hours of delivery to an Rh negative mother if the newborn is found to be D-positive or weak-D positive? Prevent future children from producing antibodies Prevent fetal cells from initially sensitizing the mother Prevent antibody response in a previously sensitized mother Neutralize any natural maternal antibodies present

Prevent fetal cells from initially sensitizing the mother Feedback The production of IgG antibodies (particularly anti-D) can have threatening consequences for the fetus. RhIg is available and prevents alloimmunization in D negative mothers exposed to D positive red cells. RhIg suppresses the immune response after exposure to D positive fetal cells and prevents the mother from producing anti-D. All Rh-negative women should receive at least one full dose of RhIg at 28 weeks gestation and another full dose after birth (within 72 hours of delivery, assuming that the newborn is found to be D-positive or weak D-positive). This situation develops from the fetal cells having the D antigen and not from fetal antibodies. Once a woman is alloimmunized and produces antibodies, the condition cannot be reversed. Anti-D is not considered a natural antibody.

A blood collection system that has a retractable needle malfunctions and causes an injury to a patient. Which of the following actions must be taken? The phlebotomist must be reprimanded The phlebotomist must be retrained The manufacturer of the device must be notified. The patient must be given a Hepatitis C vaccine.

The manufacturer of the device must be notified. Feedback One of the primary laboratory-related areas in the Safe Medical Devices Act of 1990 entails devices used during phlebotomy procedures. If it appears that a device has caused injury, it is important that the device and packaging be saved and any serial or lot numbers noted. An incident report should also be completed within 24 hours. The incident report must then be handled by the institution's "Risk Management" department (if applicable), which will file a report to the manufacturer. The problem was not related to the phlebotomist's competency to do his or her job. Retraining or reprimanding is not the required action for a medical device that malfunctions. The patient would not be given a Hepatitis C vaccine as a result of the incident.

All of the following bones contain active hematopoietic bone marrow in a normal adult, EXCEPT? Pelvis Sternum Tibia Vertebrae

Tibia. Feedback The tibia contains active hematopoietic marrow only in children (before puberty). Blood cells are manufactured in the bone marrow of all bones in a child's body. A normal, healthy adult has active cell-forming bone marrow only in the central portion of the skeleton, including the pelvis, sternum, and vertebrae. Once they reach around the age of puberty, the long bones contain only inactive, yellow (fatty) marrow.

Which of the following techniques should be used to free someone who is "frozen" to a live electrical line? Grab the victim with bare hands and immediately and pull them away Pull the electrical line away from the victim Use a non-conductive material like wood or plastic to separate the victim from the line Throw a blanket over the victim

Use a non-conductive material like wood or plastic to separate the victim from the line. Feedback If the current cannot be turned off, a non-conductive material such as a broom or chair made from wood or plastic, a rug, or a rubber mat can be used to pull or push the victim away from the source of the current. Do NOT use a wet or metal object, and do NOT touch the victim with your bare hands. Verify that the object that is used does NOT have a metal core.As an extra precaution, stand on something dry and non-conducting such as a mat or stack of paper while attempting to free the victim from the electrical current.

When performing an anti-human globulin (AHG) test, it is important to completely wash the red cells because: Washing eliminates concentrations of unbound antigens. Washing prevents elution of cell-bound antibody. Washing promotes false positive effects of rouleaux. Washing prevents neutralization of the anti-human globulin (AHG) serum.

Washing prevents neutralization of the anti-human globulin (AHG) serum. Feedback In the AHG test procedure, the source of antigen for potential reaction comes from red blood cells. Washing procedures that remove red blood cells or antigen from the testing system would invalidate any testing results. In a positive AHG test, antibody is bound to antigen after the incubation stage. Washing should not remove cell-bound antibody, nor would it prevent bound antibody from eluting from the antigen. The effects of rouleaux may be noted in test systems in which the protein content is high. Washing removes protein from the test system, so rouleaux is not a cause of false positive reactions in AHG testing. Inadequate cell washing will lead to unbound antibody remaining in the red cell suspension. This residual unbound antibody would be available to neutralize the AHG (Coombs serum), so it will not react with red blood cells (antigen) bound with antibody.