Blood Bank - Serologic and Molecular Testing
During routine inspection, a unit of unexpired blood was noticed to have a black color with numerous small clots. What is the likely cause for this observation? A. The unit was frozen B. Donor had DIC C. Viral contamination D. Bacterial contamination
D
Enzyme panel reactions cannot be used as the only source of rule-outs during antibody identification. Why is this? A. Enzyme panels only detect warm autoantibodies B. Enzyme panels only detect IgM C. All antigens on the panel cells are destroyed by enzymes D. Some antigens are destroyed and may not detect an antibody that is present
D
Essential components of compatibility testing include all of the following EXCEPT: A. Antibody screen on recipient's serum B. Major crossmatch or computer crossmatch C. ABO and Rh typing of recipient D. Direct Antiglobulin Test (DAT)
D
False negative results may occur with indirect antiglobulin tests as a result of all of the following EXCEPT: A. Undercentrifugation B. Delay in adding antiglobulin reagent C. Failure to adequately wash cells D. Red blood cells have a positive DAT
D
For granulocyte concentrations, all of the following laboratory tests must be performed on the unit by the donor center EXCEPT? A. ABO and Rh B. Red Cell antibodies C. Infectious disease markers D. Lymphocyte enumeration
D
In the antibody screening test, at what phase of reactivity is it most important to read the reactions for detection of clinically significant antibodies? A. 4°C B. Immediate spin C. 37°C D. AHG
D
Red blood cells with a positive DAT cannot be tested accurately with blood typing reagents that require an indirect antiglobulin technique unless they have been treated with all of the following (to dissociate IgG from the RBC membrane) EXCEPT: A. Chloroquine diphosphate B. Ficin C. ZZAP D. Albumin
D
The plant lectin obtained from the Dolichos biflorus plant will agglutinate which of the following? A. B cells B. O cells C. A2 cells D. A1 cells
D
The use of the direct antiglobulin test is indicated in all the following EXCEPT: A. Transfusion reactions B. Autoimmune hemolytic anemia C. Hemolytic disease of the newborn D. Detection of alloantibodies in serum
D
To determine the titer of an antibody in the serum tested against selected cells, what type of serial dilution is usually used? A. Eightfold B. Fourfold C. Threefold D. Twofold
D
What is the MOST likely cause of the ABO discrepancy when the following results were obtained from a first-time 29-year old, blood donor? Forward Group Anti-A = Negative Anti-B= Negative Reverse Group A1 Cells = Negative B Cells = 3+ A. Loss of antigen due to disease B. Acquired B C, Low immunoglobulin levels D. Weak subgroup of A
D
When performing an anti-human globulin (AHG) test, it is important to completely wash the red cells because: A. Washing eliminates concentrations of unbound antigens. B. Washing prevents elution of cell-bound antibody. C. Washing promotes false positive effects of rouleaux. D. Washing prevents neutralization of the anti-human globulin (AHG) serum.
D
Which one of the following may cause a FALSE-NEGATIVE result with antiglobulin techniques? A. Dust or dirt is present in the glass tubes used for antiglobulin testing. B. Patient or donor blood specimen was collected in silicone gel tubes. C. Patient or donor blood specimen has a positive DAT. D. Addition of AHG reagent is delayed for 40 minutes or more after final saline wash.
D
Which adsorption technique removes cold (IgM) antibodies, particularly anti-I specificities? A. Cold autoadsorption B. Warm autoadsorption C. Differential (allogeneic) D. Rabbit erythrocyte stroma (RESt)
D
Which of the following blood group antigens are most susceptible to destruction by the action of enzymes? A. D B. Jka C. Lea D. Fya
D
Which of the following choices is the basic technique used to detect unexpected antibodies with a commercial set of reagent cells? A. Polyclonal technique B. Direct antiglobulin test C. Enzyme technique D. Indirect antiglobulin test
D
Which of the following may result in a false negative reaction when performing Rh typing? A. Rouleaux B. Centrifuging too long C. Cold agglutinins D. Failure to follow manufacturer's directions precisely
D
Which of the following reagents is often used to perform a direct antiglobulin test (DAT) to determine if either IgG or complement (or both) is attached to a patient's red cells? A. Low-ionic strength solution (LISS) B. Polyethylene glycol (PEG) C. Anti-C3d D. Polyspecific AHG
D
Which of the following would be a possible cause of a positive direct antiglobulin test (DAT)? A. Transfusion reaction and warm autoimmune disease only B. Warm autoimmune disease and clot tube stored at 4°C only C. Clot tube stored at 4oC and transfusion reaction only D. Clot tube stored at 4oC, transfusion reaction, and warm autoimmune disease.
D
You perform a gel ABO/Rh test on a 45-year-old male patient and you obtain the following results. Anti-A - 4+ Anti-B - 4+ Anti-D - 4+ D control - negative A1 cells - 2+ B cells - 0 What could be the Type/Rh of this patient? a. AB POS b. A POS c. B POS d. A2B POS
D
A tech is performing an antibody screen. The reaction is negative when reading at the AHG (anti-human globulin) phase so the tech then adds Coombs' control cells. Agglutination is now observed. What does this indicate? A. The negative reaction at AHG phase is valid B. The patient's RBCs were not washed thoroughly C. Coombs' control cells are contaminated D. Coombs' control cells were not added
A
All of the following are reasons for conducting compatibility testing EXCEPT: A. Prevent recipient alloimmunization B. Verify ABO and Rh C. Select proper blood products D. Detect antibodies against donor cells
A
Which procedure should be followed when one cross-matched unit out of five is INCOMPATIBLE at the antiglobulin (AHG) phase? A. Perform a direct antiglobulin test (DAT) on the incompatible unit B. Check for high-frequency antigens C. Wash the donor cells and use the washed cells for testing D. Perform an antibody panel using donor serum
A
Which situation will cause a positive DAT (direct antiglobulin test) in the newborn? A. Hemolytic disease of the fetus and newborn B. Mother is group AB and newborn is group O C. Mother is Rh positive and newborn is Rh positive D. Mother is Rh positive and newborn in Rh negative
A
A Bombay individual's blood specimen can be differentiated from a blood specimen of a group O person by which of the following? A. Cells giving a negative reaction with anti-A,B B. Testing with anti-H lectin (Ulex europaeus) C. Reverse typing with A1 and B cells would be give different reactions D. Testing with Dolichos biflorus
B
A direct antiglobulin test (DAT) can be used to detect all of the following EXCEPT? A. Hemolytic disease of the fetus and newborn B. IgG antibodies in the patient's serum C. Hemolytic transfusion reactions D. Autoimmune hemolytic anemia
B
All of the following are advantages of performing the computer crossmatch EXCEPT? A. Greater flexibility in staffing B. One determination of recipient's ABO group is made C. Better management of blood bank inventory D. Reduced volume of sample needed on large crossmatch orders
B
In the evaluation of a positive DAT result, all of the below techniques can be used to dissociate the antibody(ies) form the RBCs EXCEPT: A. EDTA-glycine B. Saline replacement C. Chloroquine diphosphate D. Murine monoclonal antibodies
B
A ficin (enzyme) treated panel can be a useful tool for determining the identity of an antibody. On a ficin-treated panel, reactions with which system would be enhanced? A. Rh B. Duffy C. MNS D. Kell
A
A patient with multiple myeloma has the following reactions in the ABO typing: Anti-A= w+ Anti-B = w+ Anti-A,B = w+ Auto control = w+ A1 Cells = 4+ B cells = 4+ What is probably causing these results? A. Rouleaux B. Subgroup of A C. Patient has hypogammaglobulinemia D. Patient has selective IgA deficiency
A
A sample has reactions occurring at immediate spin and AHG in a panel that show varying reaction strengths. There is no obvious pattern that matches a particular panel cell or single antigen profile and the auto-control was negative. Which of the following is the most likely cause? A. An IgM and an IgG antibody B. An IgG antibody only C. An IgM antibody only D. An autoantibody
A
The major crossmatch is performed using: A. Donor's serum and recipient's red cells B. Donor's serum and recipient's serum or plasma C. Donor's red cells and recipient's serum or plasma D. Donor's red cells and recipient's red cells
C
In the Coombs phase of a crossmatch, what is the proper procedure to follow if the Check Cells give a negative reaction? A. Repeat procedure with new AHG reagent and check the cell washer. B. Add additional Check Cells and dilute with 100% distilled water. C. Add additional AHG reagent plus proteolytic enzymes to enhance the reaction. D. Accept the crossmatch results as correct - nothing further needs to be done.
A
Some soluble blood group antigens exist in fluids such as saliva, urine, and plasma. These antigens can be used to neutralize corresponding antibodies that could mask the presence of other non-neutralizable antibodies. Of the following blood group system antibodies, which one could be neutralized in a manner using these fluids or other natural sources? A. Lewis B. Kell C. Rh D. MN
A
The direct antiglobulin test (DAT) is most unreliable when diagnosing hemolytic disease of the fetus and newborn due to which blood group system? A. ABO B. Duffy C. Rh D. Kidd
A
Tube-based agglutination reactions in blood bank are graded from negative (0) to 4+. A reaction that has numerous small clumps in a cloudy, red background is: A. 1+ B. 2+ C. 3+ D. 4+
A
A 54-year-old woman has just braved a winter snow storm in North Dakota to see her doctor for a general checkup. She indicates no complaints but does mention how difficult the cold weather is for her. The doctor notices bluish coloring of her ears and fingers. She states that this has been happening for years whenever it is cold and that the problem subsides during the warm summer months. What abnormal test results might be noted in this patient's blood tests? Choose the BEST answer. A. Negative Donath-Landsteiner test B. Agglutination on blood smear C. Positive direct antiglobulin test (DAT) D. Agglutination on blood smear and positive DAT
D
When is testing for weak D optional (not required)? A. Testing for weak D on potential transfusion recipient samples. B. Testing on donor red blood cells. C. Testing cord blood on infants born to Rh-negative moms D. Testing for Rh immune globulin workups.
A
When performing an antibody panel, which one of the following antigens will be destroyed by enzyme treatment? A. Fya B. Jka C. E D. Lua
A
Which of the following best describes the direct antiglobulin (DAT) test principle? A. AHG (anti-human globulin) detects antibody already sensitized to red cells B. AHG (anti-human globulin) prevents antibody from sensitizing red cells C. AHG (anti-human globulin) is directed against cell antigens D. AHG (anti-human globulin) is directed against plasma antibodies
A
Which of the following sources of error will give a false negative result in antihuman globulin testing? A. Low pH of saline B. Dirty glassware C. Samples collected in gel separator tubes D. Refrigerated specimen
A
A former patient had an anti-E four years ago, but her antibody panel is now negative. Since she now needs blood for surgery, what should the blood bank do? A. Get autologous blood from relatives. B. Crossmatch E-negative units. C. Give group O negative whole blood. D. Give random compatible units.
B
A mother's serologic results are shown below: Group O positive Antibody Screen - Negative Her newborn types as group A Rh positive with a (1+) positive direct antiglobulin test (DAT). Which of the following investigative tests would be most useful to resolve the cause of the positive DAT and should be done FIRST? A. Test an eluate prepared from newborn's red cells against an antibody identification panel by IAT. B. Test newborn's plasma against group A1 red cells and group O antibody screen cells by IAT. C. Test newborn's plasma against mother's red cells by IAT. D. Test newborn's plasma against father's red cells by IAT.
B
Which of the following best describes reverse typing? A. Known antisera used to detect ABO antigens. B. Known antigen used to detect ABO antibodies. C. Known antigen used to detect ABO antigens. D. Known antisera used to detect ABO antibodies.
B
When testing for the quality of platelet concentrates, all of the following must be included EXCEPT? A. pH B. Platelet count C. Bacterial detection D. Gas production
D
What is the fundamental purpose of the full, pre-transfusion crossmatch? A. Detect antibodies in recipient serum/plasma that react with donor red blood cells. B. Discover HLA antibodies in graft-versus-host situations. C. Verify that the donor and recipient are the same blood type. D. Prevent hemolytic destruction of the recipient red blood cells.
A
You perform a gel ABO/Rh test on a 94-year-old woman and receive the following results. You recognize a discrepancy between the front and back types. Which one of the following reasons is most likely for this discrepancy? Anti-A - 0 Anti-B - 0 Anti-D - 4+ D control - 0 A1 cells - 0 B cells - 0 A. The patient has both a weak subgroup of A and a weak subgroup of B B. The patient is O POS with depressed ABO antibody production C. The patient has a Bombay phenotype D. Rouleaux
B
Your screen cells are 3+ at immediate spin and weak (W)+ at AHG. Your autocontrol is negative for both phases. Some of your antibody panel cells are 3+ at immediate spin and negative at AHG. What should you suspect? A. A warm autoantibody is present B. A cold antibody may be present C. Bad specimen draw D. A warm reacting alloantibody
B
A patient's serum reacts with all reagent red cell samples. The autocontrol is negative. An alloantibody to a high incidence antigen is suspected. Which of the following would most likely be a compatible donor? A. Patient's parents B. Patient's siblings C. Patient's children D. Autologous donation
D
All of the following are the reacting substances that may be in the Coombs sera (antihuman globulin) EXCEPT? A. Monoclonal antibody sources B. Polyclonal antibody sources C. Complement antibodies (e.g. anti-C3b) D. Anti-IgM sources
D
In an emergency release, why do blood bankers seldom encounter patients who have experienced hemolytic transfusion reactions (HTR) from transfusion of uncrossmatched packed RBCs? Select the best response. A. The incidence of unexpected red blood cell antibodies is relatively low. B. They usually receive group O Rh-negative red blood cells; a hemolytic transfusion reaction will never occur if O Rh-negative red blood cells are transfused. C. They hemorrhage so severely that incompatible donor red blood cells "bleed out" before a reaction occurs. D. Some patients have cold-reactive antibodies that will not react at body temperature.
A
What blood group are the RBC screening cells for antibody screens? A. Group O B. Group A C. Group B D. Group AB
A
Glycine-HCL/EDTA treatment of red cells can destroy which of the following antigens, allowing for confirmation of a suspected antibody and detecting additional antibodies? A. Kidd B. Bg and Kell C. Ss D. Duffy
B
Antibody identification interpretations would be considered correct 95% of the time or have a P value of 0.05 (5% probability that the result is due to chance) if you have: A. 2 positive reactions to rule in an antibody and 2 negative reactions to rule out an antibody B. 1 positive reaction to rule in an antibody and 3 negative reactions to rule out an antibody C. 3 positive reactions to rule in an antibody and 3 negative reactions to rule out an antibody D. 3 positive reactions to rule in an antibody and 1 negative reaction to rule out an antibody
C
IgG coated red cells are added to negative antiglobulin tests to detect which of the following sources of error? A. Delay in washing procedure B. Improper resuspension of the red cells C. Failure to add AHG D. Improper incubation time or temperature
C
Polyspecific antihuman globulin (AHG) reagent used in antiglobulin testing should react with which one of the following? A. IgG and IgA B. IgM and IgA C. IgG and C3d D. IgM and C3d
C
The AABB Standards for Blood Banks and Transfusion Services requires a control system for antiglobulin tests interpreted as negative. What is done for this control system? A. Running tests in duplicate. B. Adding an extra incubation. C. Adding IgG sensitized red cells. D. Performing a minimum of 3 extra washes.
C
The chief purpose of performing a serologic crossmatch is to: A. Identify antibodies in donor blood B. Identify antibodies in recipient red blood cells C. Identify recipient antibodies against donor cells D. Identify donor antibodies against recipient cells
C
The Lutheran b antigen (Lub) is a high incidence antigen. A patient has developed an anti-Lub. All of the screening cells and antibody identification panel cells are positive at AHG. What can be used in testing so that the blood bank can determine if there are other clinically significant antibodies present in this patient? A. Proteolytic enzymes such as ficin and papain B. Dithiothreitol (DTT) C. PEG D. Albumin
B
The concentration of sodium chloride in an isotonic solution is: A. 8.5 % B. 0.85 % C. 0.08 % D. 85%
B
What is the Indirect Antiglobulin Test (IAT) usually used to detect? A. Antibodies coating red cells B. Antibodies in the plasma C. Antigens coating red cells D. Antigens in the plasma
B
What is the maximum interval during which a recipient sample may be used for compatibility testing if the patient has recently been transfused or was pregnant within the past 3 months? A. 24 hours B. 3 days C. One week D. Two weeks
B
What is the minimum number of reactive antigen-positive and non-reactive antigen-negative panel cells that must be present in order to identify a red cell antibody with statistical confidence? A. Two B. Three C. Five D. Ten
B
When would unexpected positive reactions be encountered during ABO forward typing? A. A or B subgroups B. Antigen depression due to leukemia C. Hypogammaglobulinemia D. Acquired B antigen
D
After performing an antibody panel and a selected cell panel, you still can't rule out S and Fyb. It appears that the patient has anti-e and anti-Jkb, but they are only reacting microscopically. What technique would be the best way to strengthen the suspected antibodies? A. Lui freeze thaw technique B. Prewarm panel C. Enzyme panel D. Saline replacement technique
C
All of the following regarding Anti-A and Anti-B reagents used in forward typing for ABO typing are true EXCEPT? A. They contain monoclonal antibodies. B. The antibodies are highly specific. C. The antibodies are IgG. D. They produce an expected 3+ or 4+ reaction with the corresponding antigens.
C
or which of these reasons would a molecular method not be used? A. Determine blood type when the DAT is positive B. Complex Rh genotypes (weak D expression) C. Donor antibody screening D. Type fetal blood
C
What must be true for the antiglobulin phase of the serologic crossmatch to be omitted (i.e., immediate spin crossmatch is done)? A. The antibody screen must be negative and there is not history of detection of unexpected antibodies. B. The patient has not been transfused within the past 24 hours. C. The blood is needed for surgery. D. There is a history of detection of unexpected antibodies but the current antibody screen is negative.
A
A patient front-grouped as AB but back-grouped as O. The screening cells and auto control were positive. If the testing was performed correctly, what is the most likely cause of this discrepancy? A. Patient has two distinct cell populations B. Patient has a cold autoantibody C. Patient has missing or weakly expressed antigens D. Patient has leukemia
B
An O positive patient has no reactions at immediate spin but both screen cells are positive and all antibody panel cells are reacting 1+ at AHG. The auto control is 1+. What would you suspect to be the cause? A. Cold autoantibody B. Warm autoantibody C. Anti-Lea D. Anti-K
B
Antibodies are ruled out using panel cells that are homozygous for the corresponding antigen because: A. Multiple antibodies will not react with heterozygous cells B. Stronger reactions are seen with homozygous cells C. Heterozygous cells are usually negative D. Heterozygous cells cannot be used at all for rule outs
B
As a student in a blood bank laboratory, you are tasked with determining the identification of an antibody as part of your practical exam. You are asked to use an enzyme treated red cell panel during the process of antibody identification. Which of the following antibodies is enhanced by enzyme treatment of red cells? A. MN and Duffy antibodies B. Rh, Lewis, and Kidd antibodies C. Rh, A, B, and S antibodies D. Duffy, A, and B antibodies
B
At what frequency should quality control testing be performed on each lot of anti-human globulin to be in compliance with the FDA's current good manufacturing practices requirements? A. At the beginning of each work shift B. Each day of use C. Only at the time of receipt D. By each new user
B
What do the two and/or three reagent cells used for antibody screening detect? A. Antibodies to most white cell antigens B. Antibodies to red cell A and B antigens C. Antibodies to common alloantigens D. Antibodies to most private (low incidence) red cell antigens
C
What is the correct description for Group II discrepancies? A. These discrepancies between forward and reverse groupings are due to miscellaneous problems. B. These discrepancies between forward and reverse groupings are caused by protein or plasma abnormalities. C. These discrepancies between forward and reverse groupings are due to weakly reacting or missing antigens. D. These discrepancies between forward and reverse groupings are due to weakly reacting or missing antibodies
C
What is the explanation for a discrepancy in the following front type and back type in a newborn? Anti-A = neg Anti-B = neg A1 cells = neg B cells = neg A. Red cells are totally coated with antibody. B. The newborn is missing antigens. C. The baby's antibodies are undeveloped. D. Unable to determine.
C
What procedure is used by the laboratory personnel to confirm ABO typing by using cells with known blood groups? A. DAT B. Forward typing C. Reverse typing D. Antibody identification panel
C
All of the following could explain why screening cell #2 has a stronger reaction than screening cell #1 EXCEPT: A. The patient has more than one antibody and all corresponding antigens are on screen cell #2 but not on screen cell #1. B. The patient has an antibody other than anti-D and screen cell #2 has a double dose of the antigen, whereas cell #1 has only a single dose. C. Operator variability - When dislodging the cell buttons during reading, the technologist shook screen cell #1's test more vigorously than cell #2's test. D. Screening cell #1 has homozygous antigen for the reacting antibody whereas screening cell #2 is heterozygous.
D
Coombs control check cells used to verify negative reactions at the anti-globulin (IAT) phase are coated with: A. Anti-P1 B. Anti-M C. IgM antibodies D. IgG antibodies
D
Chloroquine diphosphate can be used in blood banking for which of the following methodologies? A. To remove antibody bound to red cells so that cells can be further tested B. To remove an specific antibody in serum or plasma C. To remove ABO antigens from cells D. To remove Rh antigens from cells
A
How long after collection can a patient's sample be used for compatibility testing? A. 72 hours B. 24 hours C. 96 hours D. 7 days
A
If the unit is going to be transfused within the collection facility, autologous blood must always be tested for which of the following before transfusion? A. ABO, Rh B. ABO, Rh, HBsAg C. ABO, Rh, HIV D. ABO, Rh, HBsAg, HIV
A
In order to detect the presence of antibodies fixed on the RBC's of newborns one should: A. Perform a direct antiglobulin test (DAT) on the cord blood B. Perform an indirect antiglobulin test (IAT) on the cord blood C. Test the baby's cells with typing antiserum D. Look for agglutination in a mixture of mother's serum and baby's cells
A
Which of the following groups of antibodies generally reacts most strongly at room temperature or 4oC? A. Anti-P1, anti-Leb, anti-M B. Anti-K, anti-Lua, anti-Fya C. Anti-S, anti-Jkb, anti-Leb D. Anti-K, anti-Lub, anti-s
A
Which of the following is the proper temperature to use when crossmatching in the presence of a cold antibody? A. 37º C B. 25º C C. 15º C D. 4º C
A
FALSE-NEGATIVE results at the indirect antiglobulin phase of an antibody screening test using a tube method (i.e., not a Gel-method) are usually caused by which of the following? A. Excessive washing of the red cells B. Inadequate washing of the red cells C. Warm autoantibody present in the patient's serum D. Cold autoantibody present in the patient's serum
B
In blood bank agglutination reactions, the zeta potential (a force exerted by ions in the saline solution that causes repulsion between red blood cells in the saline suspension) can be reduced by treating the sensitized cells with: A. Polyclonal antibody reagents B. Polyethylene glycol (PEG), albumin, or proteolytic enzymes C. Monoclonal antiglobulin reagents D. Coombs check cells
B
What is the most prudent step to follow to select units for crossmatch after recipient antibodies have been identified? A. Perform DAT on patient serum and donor units B. Antigen type patient cells and any donor cells to be crossmatched C. Perform IAT on patient cells and donor units D. Obtain a different sample for repeat antibody panel testing
B
What should be done if all forward and reverse ABO results are NEGATIVE? A. Perform additional testing with anti-A1 lectin and anti-A,B. B. Incubate at room temperature or 4°C to enhance weak expression. C. Perform testing with new reagents and retype. D. Perform an antibody screen.
B
When performing an antibody screen, both the screen cells are 4+ at immediate spin and W+ at AHG. The antibody panel shows 4+ reactions at immediate spin and W+ reactions at AHG and there is no specific match to the reaction pattern. The auto control is negative. What would be a logical next step? A. Have patient redrawn B. Repeat testing using warmed patient sample/reagent and just do AHG reading C. Run an enzyme panel D. Use acidified reagents
B
Which of the following accurately represents reverse typing? A. Reverse typing is performed using known reagent antisera to detect ABO antigens on the patient's red blood cells. B. Reverse typing is performed using known reagent red blood cells to detect ABO antibodies in the patient's serum or plasma. C. Reverse typing is performed using known reagent screening cells to detect clinically significant antibodies in the patient's serum or plasma. D. Reverse typing is performed using known reagent antisera to phenotype donor red blood cells for clinically significant antigens.
B
Which of the following is the MOST likely discrepancy seen when a person demonstrates an "acquired B-antigen" phenomenon? A. Forward typing appears to be B, but reverse group type is O. B. Forward typing appears to be AB, but reverse group type is A. C. Forward typing appears to be AB, but reverse group type is B. D. Forward typing appears to be B, but reverse group type is AB.
B
An antibody screen utilizing polyethylene glycol (PEG) was performed. Reaction readings of this antibody screen are analyzed after immediate spin and again at 37°C incubation with subsequent centrifugation. How will the centrifugation of the tubes affect the patient's results? A. Reactions will be enhanced B. No effect will be seen C. False positives may be seen D. False negatives may be seen
C
What should be done FIRST if a donor unit of red blood cells is found to be incompatible at the antiglobulin phase but compatible at immediate spin with several different recipients? A. Repeat the ABO grouping on the incompatible unit using different sera B. Do a panel made up of red cells having all low-frequency antigens C. Perform a direct antiglobulin test (DAT) on the donor unit D. Obtain a new specimen and repeat the minor crossmatch
C
What two things are put together for the testing known as forward grouping (testing)? A. Patient red cells and patient serum B. Reagent red cells and patient serum C. Reagent antisera and patient red cells D. Patient serum and donor red cells
C
When is a computer crossmatch acceptable? A. Patient has a history of anti-Jka but the antibody screen on the current sample is negative B. Patient has a positive antibody screen and anti-D is detected C. Patient has no history of clinically significant antibodies detected and the antibody screen on the current sample is negative D. Patient has a history of anti-Fya but the antibody screen on the current sample is negative
C
Which of the following might cause a false positive indirect antiglobulin test (IAT)? A. Failure to adequately wash cells. B. Delay in the addition of antiglobulin reagent. C. Over-centrifugation D. High concentration of IgG paraprotein in a patient's serum.
C
A patient transfused with two units of packed cells spiked a fever of 99.5oF and complained of chills five days after transfusion. The direct antiglobulin test (DAT) was positive with anti-IgG, but negative with anti-C3d. Compatibility testing was performed on the pre- and post-transfusion specimens. The post-transfusion specimen was incompatible with one of the donor units transfused. An antibody screen was done on both the pre- and post-transfusion specimens. An antibody was detected in the post-transfusion specimen only and identified by panel studies as anti-Jka. This transfusion reaction is most: A. Post-transfusion purpura B. An anaphylactic response C. An acute hemolytic transfusion reaction D. A delayed hemolytic transfusion reaction
D
An elution is a technique that is used to release, concentrate, and purify antibodies that are bound to red blood cells. In preparing red cells for any elution method, one must be particularly careful to: A. Leave a small amount of serum in the test system so complement will be present B. Add albumin to decrease zeta potential C. Pretreat the cells with enzymes D. Thoroughly wash sensitized red cells
D
