BB Flashcards

Question

7. Which typing results are most likely to occur when a patient has an acquired B antigen? A. Anti-A 4+, anti-B-3+, A1 cells neg, B cells neg B. Anti-A 3+, anti-B neg, A1 cells neg, B cells neg C. Anti-A 4+, anti-B 1+, A1 cells neg, B cells 4+ D. Anti-A 4+, anti-B 4+, A1 cells 2+, B cells neg

Answer 1

C In forward typing, a 1+ reaction with anti-B is suspicious because of the weak reaction and the normal reverse grouping that appears to be group A. This may be indicative of an acquired antigen. In the case of an acquired B antigen, the reverse grouping is the same for a group A person. Choice A is indicative of group AB; choice B is indicative of a group A who may be immunocompromised. Choice D may be caused by a mistyping or an antibody against antigens on reverse cells.

Answer 2

A The A1B blood group has the least amount of H antigen. This occurs because both A and B epitopes are present on RBCs, compromising the availability of H epitopes. A1B cells will yield weak reactions with anti-H lectin.

Answer 3

B A person who is in need of RBC transfusion and is an A2 with anti-A1 can be transfused with A or O cells because the anti-A1 is typically only reactive at room temperature.

Answer 4

A These results point to a cold autoantibody. Washing the cells with warm saline may elute the autoantibody, allowing a valid forward type to be performed. The serum should be adsorbed using washed cells until the autocontrol is negative. Then, the adsorbed serum should be used for reverse typing.

Answer 5

B All negative results may be caused by weakened antigens or antibodies. Room temperature or lower incubation temperature may enhance expression of weakened antigens or antibodies

Answer 6

C The immunodominant sugar N-acetyl-galactosamine confers A antigen specificity when present at the terminus of the type 2 precursor chain on the RBC membrane. Therefore, its presence would cause RBCs to react with anti-A1 lectin, Dolichos biflorus

Answer 7

C The transplant recipient is probably taking immunosuppressive medication to increase graft survival. This can contribute to the loss of normal blood group antibodies as well as other types of antibodies

Answer 8

D Anti-A,B should react positively with group A or B and any subgroup of A or B (with exception of Am). An A1 (not A2) would react with anti-A1 lectin; only an A2 person with anti-A1 would give a positive reaction with A1 cells; an A2 would react more strongly with anti-H than A1.

Answer 9

B The patient is most likely an AB person who has formed a cold-reacting alloantibody reacting with B cells and O cells. An identification panel should be performed. An acquired B person or someone with hypogammaglobulinemia should not make antibody that would agglutinate O cells.

Answer 10

C Excessive A substance, as may be found in some types of tumors, may be neutralizing anti-A. Weak A subgroups may fail to react with anti-A and require additional testing techniques (e.g., room-temperature incubation) before their expression is apparent.

Answer 11

C The reverse typing should agree with the forward typing in this result. The 4+ reaction with anti-B indicates group B. A positive reaction is expected with A1 cells in the reverse group.

Answer 12

D In a transplantation scenario, there are no methods to employ to solve the discrepancy. The medical laboratory scientist must rely on the patient history of donor type and recipient type and the present serological picture. Giving a B-positive recipient an O-positive transplant constitutes a minor ABO mismatch. The forward type resembles the donor. The reverse type still resembles the recipient. The ABO type reported out does not fit a pattern resulting in an undetermined type.

Answer 13

B Rh positive refers to the presence of D antigen; Rh negative refers to the absence of D antigen. These designations are for D antigen only and do not involve other Rh antigens.

Answer 14

A This individual has D antigen and is classified as Rh positive. Any genotype containing D antigen will be considered Rh positive

Answer 15

A If a person has a positive DAT, the RBCs are coated with immunoglobulin. If a test for weak D were performed, the test would yield positive results independent of the presence or absence of D antigen on the RBCs.

Answer 16

D The designation r’ is dCe and ry is dCE, neither of which contains c antigen. The other three Rh types contain c antigen and could not be used in transfusion for a person with anti-c.

Answer 17

C The phenotype that results from D–/D– is classified as enhanced D because it shows a stronger reaction than expected with anti-D. Such cells have a greater amount of D antigen than normal. This is thought to result from a larger quantity of precursors being available to the D genes because there is no competition from other Rh genes.

Answer 18

A Detection of ABO and Rh antigens and antibodies requires different reaction conditions. ABO antibodies are naturally occurring IgM molecules and react best at room temperature. Rh antibodies are generally immune IgG molecules that result from transfusion or pregnancy. Detection may require 37°C incubation and/or enhancement techniques

Answer 19

A Blood tested for weak D that shows 1+ reaction after IAT is classified as Rh positive. The weak D designation is not noted in the reporting of the result.

Answer 20

D Only rr (dce/dce) does not contain C antigen. A person will form alloantibodies only to the antigens he or she lacks.

Answer 21

B The genotype rr (dce/dce) lacks D, C, and E antigens and would be suitable for an individual who has developed antibodies to all three antigens. This is the most common Rh-negative genotype and is found in nearly 14% of blood donors who are white.

Answer 22

D The D antigen comprises different parts designated as a mosaic. If an individual lacks parts of the antigen, he or she may make antibodies to the missing parts if exposed to the whole D antigen

Answer 23

A DcE/DcE (R2R2) is not possible because R2 can be inherited only from the mother and is not present in the father.

Answer 24

D Weak D phenotypes 1, 2, and 3 (as well as 4) are not associated with formation of anti-D negating RhIg prophylaxis. Weak D phenotypes 5, 11, 15, 19, and 20 would require RhIg prophylaxis

Answer 25

B The R1R1 (DCe/DCe) individual does not have the E or c antigen, and could make anti-E and anti-c antibodies when exposed to R2R2 cells (DcE/DcE).

Answer 26

C A person who is Rhnull shows no Rh antigens on his or her RBCs. Loss of Rh antigens is very unlikely to happen because Rh antigens are integral parts of the RBC membrane. The Rhnull phenotype can result from either genetic suppression of the Rh genes or inheritance of amorphic genes at the Rh locus.

Answer 27

D Weak D testing requires both 37°C incubation and the IAT procedure. Anti-D is an IgG antibody, and attachment of the D antigen is optimized at warmer temperatures. AHG in the IAT phase facilitates lattice formation by binding to the antigen–antibody complexes

Answer 28

A An Rh-negative control (patient cells in saline or 6% albumin) should be run if a sample appears to be AB positive. The ABO test serves as the Rh control for other ABO types.

Answer 29

C Wiener proposed a single-locus theory for Rh, with multiple alleles determining surface molecules that embody numerous antigens.

Answer 30

C The Wiener designation for the E antigen is rh”. The Wiener designation hr’ denotes c, hr” denotes e, and Rh0 is D.

Answer 31

B Although giving Rh-positive RBCs to an Rh-negative patient would not harm the patient in this case, because he is male, giving A negative would be the first choice. You should not expose a patient to the D antigen, if possible, and the residual anti-B in a unit of A-negative packed cells is less immunogenic than giving B or O RBCs.

Answer 32

A The Gel system cannot detect a weak D phenotype because there is no washing phase in the Gel system.

Answer 33

C Anti-Lea is produced primarily by persons with the Le(a-b-) phenotype because Le(ab+) persons still have some Lea antigen present in saliva. Although Lea is not present on their RBCs, Le(a-b+) persons do not form anti-Lea.

Answer 34

B Saliva from an individual with the Le gene contains the Lea antigen. This combines with anti-Lea, neutralizing the antibody. Panel cells treated with DTT (0.2M) lose reactivity with anti-K and other antibodies, but not anti-Lea. Hydatid cyst fluid neutralizes anti-P1.

Answer 35

A Lewis antibodies are generally not considered clinically significant unless they react at 37°C or at the IAT phase. The antibody must be honored in this scenario due to its reactivity at the IAT phase of testing.

Answer 36

B Dosage effect is the term used to describe the phenomenon of an antibody that reacts more strongly with homozygous cells than with heterozygous cells. Dosage effect is a characteristic of the genotype MN because the M and N antigens are both present on the same cell. This causes a weaker reaction than seen with RBCs of either the MM or NN genotype, which carry a greater amount of the corresponding antigen.

Answer 37

A Although anti-M may not be clinically significant, a strongly reacting anti-M that persists through to the IAT phase may interfere with detection of a clinically significant antibody that reacts only at IAT.

Answer 38

A The Donath-Landsteiner antibody has anti-P specificity with biphasic activity. The antibody attaches to RBCs at 4°C and then causes the RBCs to hemolyze when warmed to 37°C.

Answer 39

D Hydatid cyst fluid contains P1 substance, which can neutralize anti-P1 antibody.

Answer 40

B Anti-e is frequently implicated in cases of WAIHA. The corresponding antigen is characterized as high frequency in the Rh system and can mask the presence of other alloantibodies.

Answer 41

A Adult cells contain mostly I antigen, and anti-I would react with all adult cells found on screen or panel cells. Cord blood cells, however, contain mostly i antigen and would test negative or only weakly positive with anti-I.

Answer 42

C Antibodies to the M and N antigens are IgM antibodies commonly found as cold agglutinins.

Answer 43

C Anti-Sda characteristically gives a refractile mixed-field agglutination reaction in the IAT phase. The refractile characteristic is more evident under the microscope.

Answer 44

C The 3+3 rule ascertains correct identification of antibody at a confidence level of 95%. For this level to be met, reagent RBCs are found containing target antigen to suspected antibody that react in test phase; likewise, reagent RBCs devoid of antigen will not react in test phase.

Answer 45

B k antigen is found with a frequency of 99.8%; therefore, k-negative individuals are rare. Because of this, the occurrence of anti-k is also rare.

Answer 46

B Enzyme-treated cells will not react with Duffy antibodies. Rh antibodies react more strongly with enzyme-treated RBCs. An enzyme panel, therefore, would enhance reactivity of anti-e and destroy reactivity to anti-Fya.

Answer 47

A Anti-Fya, anti-Jka, and anti-K are usually detected at IAT and all may cause HDFN and transfusion reactions that may be hemolytic. Reactivity with anti-Fya is lost with enzyme-treated RBCs, but reactivity with anti-Jka is enhanced with enzyme-treated cells. Reactivity with anti-K is unaffected by enzyme-treated cells.

Answer 48

A The Kidd antibodies are notorious for disappearing from serum, yielding a negative result for the antibody screen. If a patient has a history of a Kidd antibody, blood must be crossmatched using antigen-negative units. If the patient is transfused with the corresponding antigen, an anamnestic response may occur with a subsequent hemolytic transfusion reaction.

Answer 49

C HTLA antibodies may persist in reaction strength, even when diluted. These antibodies are directed against high-frequency antigens (e.g., Cha). They are not clinically significant but, when present, are responsible for a high incidence of incompatible crossmatches.

Answer 50

C Of the antibodies listed, only Lub is detected in the IAT phase, causes in vitro hemolysis, may cause HDFN, and does not react with DTT-treated cells.

Answer 51

B Serum stored at 4°C for no longer than 48 hours preserves complement activity. Plasma is inappropriate because most anticoagulants chelate calcium needed for activation of complement. Heating the serum to 56°C destroys complement.

Answer 52

B ABO antibodies are not detected by group O screening cells because O cells contain no A or B antigens.

Answer 53

B The pattern clearly fits that of anti-Jkb, an antibody that usually reacts best at IAT. The weaker reactions are caused by the dosage effect found on cells that are heterozygous for the Jkb antigen.

Answer 54

B When patient serum is available, it will be crossmatched with donor cells. Patient serum might contain antibodies against antigens on donor cells that may destroy donor cells. If an incompatibility is discovered, the problem will be reported immediately to the patient’s physician.

Answer 55

C Autoantibodies may cause positive reactions with screening cells, panel cells, donor cells, and patient cells. The DAT result will be positive; however, DAT is not included in compatibility testing.

Answer 56

B High-frequency alloantibodies or a mixture of alloantibodies may cause all three screening cells to be positive. A negative autocontrol would rule out autoantibodies

Answer 57

C A minor crossmatch consists of recipient RBCs and donor serum or plasma.

Answer 58

A Compatibility testing may be performed on a patient sample within 3 days of the scheduled transfusion; however, if the patient is pregnant or was transfused within 3 months, the sample must be less than 3 days old.

Answer 59

B An AB person is the universal recipient and may receive any blood type; because only a type and screen were ordered and blood may not be used, check inventory for A-, B-, and O-negative units.

Answer 60

B An O-negative individual has no A or B antigens and may donate RBCs to any other ABO type.

Answer 61

B An O-negative individual has both anti-A and anti-B and may receive only O-negative RBCs.

Answer 62

C Leaking may indicate a broken seal or a puncture, which indicates possible contamination of the unit, even if the RBCs appear normal. The unit should be discarded

Answer 63

D Compatibility testing would not be affected if the donor has anti-K in his or her serum. This is because the major crossmatch uses recipient serum and not donor serum. Other tests, such as ABO, Rh, and antibody screen on the recipient, also would not be affected

Answer 64

D ABO determinations must be concordant on at least two occasions, including the current sample.

Answer 65

D Anti-k (Cellano) is a high-frequency alloantibody that would react with screening cells and most donor units. The negative autocontrol rules out autoantibodies. Anti-H and anti-S are cold antibodies and anti-Kpa is a low-frequency alloantibody

Answer 66

A A cold alloantibody would show a reaction with screening cells and donor units only at the IS phase. The negative autocontrol rules out autoantibodies and abnormal protein.

Answer 67

C The incompatible donor unit may have an antibody coating the RBCs, or the patient may have an alloantibody to a low-frequency antigen. An alloantibody to a highfrequency antigen would agglutinate all units and screening cells.

Answer 68

A The incompatible unit may have RBCs coated with antibody and/or complement. If RBCs are sensitized, then some problem exists with the donor. Discard the unit.

Answer 69

C An abnormal protein or nonspecific autoantibody would cause antibody screen, crossmatch, and patient autocontrol to be positive. Alloantibodies would not cause a positive patient autocontrol

Answer 70

B Antigen typing or phenotyping of the patient’s cells confirms the antibody identification; antigen typing of donor cells helps ensure the crossmatch of compatible donor units

Answer 71

D The unit may be used in the general blood inventory, if it is properly labeled and only cellular elements are used.

Answer 72

C A positive DAT using anti-IgG indicates that antibodies are coating the patient’s cells. An eluate would be helpful to remove the antibody, followed by a cell panel to identify it.

Answer 73

B The reaction pattern fits that of a cold antibody reacting at the IS phase and of sufficient titer to persist at 37°C incubation. The reactions disappear in the IAT phase.

Answer 74

A Rouleaux may be dispersed or lessened by using the saline replacement technique. This involves recentrifuging the tube, then withdrawing serum and replacing it with two drops of saline. The tube is respun and examined for hemolysis.

Answer 75

D Antibodies causing a positive DAT would be coating RBCs and would require elution, not adsorption, to identify them.

Answer 76

C According to the American Association of Blood Banks (AABB) standards, the recipient sample must be kept for 7 days after compatibility testing.

Answer 77

B For transfusion of platelets and plasma, there is no required protocol for crossmatching.

Answer 78

A The only requirement for transfusing an autologous unit is a check of the ABO and Rh types.

Answer 79

A The type chosen should be A-positive RBC units. Although all choices would be compatible, the first choice should be A-positive because this unit will contain residual plasma anti-B. Anti-B is less immunogenic than anti-A, which would be present, albeit in small amounts, in B-positive and O-positive units.

Answer 80

B The abbreviated crossmatch usually consists of a type and screen and an IS crossmatch.

Answer 81

B IS crossmatching may be performed when the patient has no history of antibodies and the current antibody screen is negative.

Answer 82

B Over 90% of transfusion reactions are caused by some type of clerical error. The most time-saving approach would be to check all paperwork before performing any laboratory testing

Answer 83

D Anaphylactic or anaphylactoid reactions are the most severe form of allergic transfusion reaction and are associated with deficient or absent IgA in the patients, allowing the formation of anti-IgA. These patients must be transfused with washed cellular products where the plasma has been removed.

Answer 84

B A transfusion reaction that occurs several days after a transfusion of blood products is probably a delayed immunologic reaction as a result of an antibody formed against donor antigens. This is a classic example of a reaction caused by an antibody, such as anti-Jka.

Answer 85

C TRALI is associated with antibodies to human leukocyte antigens or neutrophil antigens, which react with the patient’s granulocytes and cause acute respiratory insufficiency.

Answer 86

C FNHTR is defined as a rise in temperature of greater than 1°C above 37°C, associated with transfusion and unexplained by other causes. The patient has formed antibodies to HLA, which reacted with donor cells and resulted in release of pyrogens.

Answer 87

B Group A blood given to a group O patient would cause an immediate hemolytic transfusion reaction because a group O patient has anti-A and anti-B antibodies and would destroy A cells.

Answer 88

C This is an example of an anamnestic reaction, where the patient was most likely exposed to the Jkb antigen at some point in his life, and upon re-exposure to the antigen, the antibody titer rose to detectable levels. This resulted in positive DAT and post-transfusion antibody screen results.

Answer 89

D The preliminary evaluation of a transfusion reaction includes checking the color of serum and performing ABO and Rh checks and DAT on the post-transfusion sample. A panel would not be part of the preliminary workup.

Answer 90

C The temperature rose from 37.1°C to 38.3°C. The DAT result was negative, and although blood was found on the urinalysis, microscopic RBCs were also found. Because intact RBCs are not caused by a transfusion reaction, the cause of hematuria was not likely transfusion related. A febrile nonhemolytic reaction is highly consistent with both symptoms and post-transfusion test results.

Answer 91

D The tachycardia, increased pulse, and volume transfused before a reaction was called are consistent with volume overload. The temperature change did not meet criteria for a febrile reaction, and evidence for a hemolytic reaction is lacking.

Answer 92

B This case emphasizes the statistic that not all causes of death are related to transfusion. The temperature dropped ruling out a febrile reaction; there was no evidence of pulmonary edema or hypotension seen with TRALI (and plasma products are more associated with TRALI compared with RBCs); and there was no sign of hives or itching, which are often associated with an allergic reaction

Answer 93

A This case represents an acute hemolytic reaction where the patient had previous sensitization to E and c antigens. Given the history of anti-Fya, an assumption was made that anti-Fya was the cause of the positive reverse type with A1 cells, even though this antibody does not react at the IS phase. This brings to light the importance of running a panel whenever the patient has a positive antibody screen, regardless of previous results. Hemoglobinuria, a positive DAT, and the hemolyzed post-transfusion specimen all are consistent with an acute hemolytic reaction.

Answer 94

A This example represents a situation where the pathologist was not provided with all information needed to interpret the reaction. There was no information on patient symptoms, the patient had received another unit of RBCs hours previously with no problems, and a postreaction specimen was not collected. Therefore, any serological abnormalities could not be identified. The U.S. Food and Drug Administration (FDA) recommends collecting a postmortem specimen if a reaction is called so that the investigation of transfusion reaction can be completed. In this case, the pathologist interpreted the reaction as not related to transfusion because no symptoms were documented.

Answer 95

C One unit of RBCs will raise the hemoglobin level by approximately 1.0 to 1.5 g/dL, and the hematocrit by 3% to 4%. Results vary, depending on the age of the blood and the patient’s blood volume and hydration status. Six units will raise the hemoglobin level to at least 12 g/dL.

Answer 96

D Removal of the buffy coat, which contains both platelets and white blood cells (WBCs), is not an approved method for leukocyte reduction of RBCs. The other methods can be employed to achieve a leukocyte reduction of less than 5 × 106.

Answer 97

A There is a 30-minute time limit for a unit of RBCs that is not kept under proper storage conditions (1°C–6°C).

Answer 98

B Platelet preparation from whole blood must be done within 8 hours of collection.

Answer 99

A Rejuvenated RBCs may be prepared within 3 days of the outdate of the unit and washed and transfused or frozen within 24 hours. A unit of RBCs may be frozen within 6 days of collection. An RBC unit can be irradiated any time prior to the expiration date; once irradiated, the unit must be transfused within 28 days of irradiation or the original outdate, whichever comes first. Leukocyte-reduced RBCs should be prepared within 6 hours of collection, but must be given within 24 hours, if prepared using an open system. Leukocyte-reduced RBCs prepared using a closed system may be kept until the original date of expiration.

Answer 100

C Single-donor platelets prepared by apheresis must contain a minimum of 3.0 × 1011 platelets, and pH must be 6.2 or higher throughout the shelf life of the product.

Answer 101

B Patients with CGD cannot fight bacterial infections because of dysfunctional phagocytic enzymes; granulocyte concentrates are the product of choice for these patients

Answer 102

C The FDA has mandated that pH and glucose can no longer be used as a screening test for platelets. The Verax PGD assay has been FDA approved for both single-donor platelets and random-donor platelets for bacteria screening.

Answer 103

A FFP must be prepared within 8 hours after collection or according to FDA-cleared operator manual/inserts.

Answer 104

C A patient having cold agglutinins might have a reaction to a cold blood product. The product should be warmed to 37°C before transfusion.

Answer 105

A The other half unit must be issued within 24 hours, if an open system is used to split the unit

Answer 106

D A unit having a noticeable clot should not be issued for transfusion to a patient. The clot may be an indication of contamination or bacterial growth

Answer 107

C Cryoprecipitate may be used to treat von Willebrand disease, hypofibrinogenemia, and factor XIII deficiency, but is not indicated in ITP. IVIG is the product of choice for ITP.

Answer 108

C In the event of an ABO-mismatched stem cell transplant, special attention must be paid to the choice of transfused blood products. Type A or AB platelets may be given to a transplant in which the donor is type A and the recipient is type O; once the stem cells engraft, platelets/plasma must be compatible with type A cells. If only type O single-donor platelets are available, the product can be spun down using a centrifuge and plasma can be removed. Then, a sterile connecting device can be used to aseptically transfer sterile isotonic saline to the platelet product, replacing the incompatible plasma.

Answer 109

C Patients with anti-IgA antibodies should not receive components containing plasma. Washed or deglycerolized RBCs can be issued.

Answer 110

B Expiration of pooled cryoprecipitate must take into account that there may be units that makeup the pool with differing collection dates where the earliest date is used to determine the expiration date.

Answer 111

C Washed RBCs renders the system “open” and shortens the expiration time to 24 hours.

Answer 112

D Platelets require constant agitation and are stored at temperatures between 20°C and 24°C. Cold-stored platelets (single donor [apheresis] platelets stored at 1-6°C for up to 3 days) may be used for actively bleeding patients, but are not approved for treating thrombocytopenia.

Answer 113

D WAIHA would not require irradiation unless the patient had an underlying immunosuppressive disorder

Answer 114

C An RBC unit that has been leukocyte reduced must retain 85% of original RBCs

Answer 115

C Granulocyte concentrates contain a large amount of RBCs (greater than 2 mL) that must be crossmatched with the recipient’s serum.

Answer 116

B If an MLS mistakenly irradiates a unit of RBCs more than once, the unit must be discarded because of subsequent potassium accumulation. This does not apply to platelets.

Answer 117

A FFP requires dry ice for shipment. Frozen RBCs and cryoprecipitate also require dry ice.

Answer 118

A A thawed unit of pooled cryoprecipitate must be dispensed within 4 hours unless a sterile connecting device was used, which would extend expiration to 6 hours.

Answer 119

A Gamma rays or x-rays have the ability to prohibit a lymphocyte’s ability to divide, preventing TA-GVHD.

Answer 120

C Frozen RBCs may be kept for up to 10 years, or longer if the transfusion service or blood center has a policy for extension beyond 10 years. FFP and cryoprecipitate stored at –18°C or lower expire in 1 year. If FFP is kept at –65°C or lower, the expiration time is 7 years. Platelet concentrates expire from 24 hours to 5 days, depending on the collection system used.

Answer 121

A Single-donor platelets require more preparation time compared with random-donor platelets because they are prepared by apheresis, which may require 1 to 3 hours, depending on the instrumentation used. Pooling random donor platelets in equivalent amounts may require only a few minutes

Answer 122

A When individual cryoprecipitate units are pooled in an open system, the expiration time is 4 hours; if cryoprecipitate is pooled using a sterile connecting device, the expiration time is 6 hours

Answer 123

B RBCs that have been leukocyte reduced must have fewer than 5 × 106 WBCs per unit.

Answer 124

D The patient with cancer may be immunocompromised because of the medication used but needs to receive RBCs for anemia; therefore, irradiated RBCs are indicated. Platelets may be needed to control bleeding, and granulocytes may be indicated for short-term control of severe infection.

Answer 125

A If the donor is symptom free, there is no deferral period for the hepatitis B vaccine. Persons who have had body piercing are given a 12-month deferral. Persons who lived in an area endemic for malaria or who received antimalarial drugs are deferred for 3 years. A positive test for the hepatitis C virus (HCV) is cause for indefinite deferral.

Answer 126

C Her age and hemoglobin meet donor criteria. However, because she is currently on warfarin, only RBCs can be prepared from her donation.

Answer 127

A Deferral for HBIG injection is 12 months. Deferral for rubella vaccine is 4 weeks. The deferral period for influenza and yellow fever vaccines is 2 weeks.

Answer 128

B A plateletpheresis donor must wait at least 48 hours between donations. The waiting period following an autologous donation is at least 3 days. An 8-week interval must pass between all other types of donations.

Answer 129

A To be eligible for plateletpheresis, the platelet count should be greater than 150 × 109/L for a frequent platelet donor. Plasma loss exceeding 1,000 mL would be cause for rejection, but not 800 mL. A donor may donate 24 times a year, but not as frequent as once every 2 days in a 7-day period. A donor cannot ingest aspirin within 36 hours of platelet donation.

Answer 130

B Athletes may have a pulse below 50 and may still be acceptable as blood donors. Drug addiction is cause for permanent deferral, as is a major illness. The deferral period after treatment for syphilis or gonorrhea is 12 months.

Answer 131

D Diastolic pressure must not be higher than 100 mm Hg. Donors weighing less than 110 lb may donate up to 12% of their blood volume (volume = weight in kg/50 × 450 mL). Oral temperature must not be greater than 37.4°C (99.5°F). BP limits for donation are 180 mm Hg for systolic and 100 mm Hg for diastolic pressure. The limit for hemoglobin is 12.5 g/dL and for hematocrit 38%.

Answer 132

D An accidental needlestick would not be a cause for indefinite deferral of a donor. The deferral period is 1 year.

Answer 133

A Clopidogrel (Plavix) renders platelets nonfunctional, and therefore potential donors on this medication cannot donate platelets

Answer 134

A To determine the amount of anticoagulant to remove when the donor is less than 110 lb, divide weight by 110 lb, and multiply by 450 mL; divide that number by 100, and multiply by 14 (this gives the anticoagulant volume needed); then subtract this from 63 mL, which is the standard volume of anticoagulant in a 450 mL bag. The result is the amount of anticoagulant to remove.

Answer 135

C This woman is hyperventilating; therefore, the donation should be discontinued. A paper bag should be provided to the donor to breathe into to increase the carbon dioxide in the donor’s air.

Answer 136

C If blood flow has stopped, check the needle first. If blood flow does not resume after repositioning, then withdraw the needle and discontinue the donation. Do not perform a second venipuncture on the donor.

Answer 137

A The 45-year-old man with alloanti-k is the best candidate for predeposit autologous donation because compatible blood will be hard to find if he needs blood after surgery. The other candidates may not be good choices for donation because the process may prove harmful to them.

Answer 138

A An autologous donor can donate up to 72 hours before expected surgery.

Answer 139

D A unit of whole blood should be collected within 15 minutes.

Answer 140

B In acute normovolemic hemodilution, one or more units of blood are removed from the donor and replaced with crystalloid or colloid. Blood may be stored at room temperature for up to 8 hours or at 1°C to 6°C for up to 24 hours. Bleeding during surgery results in less RBC loss after hemodilution, and the autologous RBCs are infused after bleeding stops. Such units are for autologous transfusion only.

Answer 141

A The minimum hematocrit for a double RBC donation is 40%.

Answer 142

D This is a common scenario with women who have recently married, and have not changed their license or other form of identification given to the collection facility. Checking that other demographic information matches is sufficient, if approved by the medical director, because an autologous unit is very difficult to replace in time for surgery.

Answer 143

C In most states, the youngest age a person can donate is 16 years with parental permission

Answer 144

C Men who have sex with men can donate blood if they have not had sex with another man in the past year.

Answer 145

D Immune anti-K from the mother would not coat the baby’s RBCs if they did not contain the K antigen; therefore, the DAT result would be negative.

Answer 146

B If the fetal screen or rosette test has a negative result, indicating the fetal maternal blood is negligible in a possible RhIg candidate, standard practice is to issue one dose of RhIg

Answer 147

A The identification of the antibody is very important at this stage of the pregnancy. If the antibody is determined to be clinically significant, then a titer may determine the strength of the antibody and the need for clinical intervention

Answer 148

C Transfusion of antigen-positive cells to the mother who already has an antibody might cause a transfusion reaction and/or evoke an even stronger antibody response, possibly causing more harm to the fetus.

Answer 149

A If the cord blood cells contain excessive Wharton jelly, then further washing or obtaining another cord blood sample will not solve the problem. A heelstick sample will not contain Wharton jelly and should give a valid DAT result.

Answer 150

B Anti-D is the only antibody for which prevention of HDFN is possible. If a pregnant woman develops anti-K, she will be monitored to determine if the antibody level and signs of fetal distress necessitate clinical intervention.

Answer 151

C RhIg is immune anti-D and is given to Rh-negative mothers who give birth to Rhpositive babies and who do not have anti-D already formed from previous pregnancies or transfusion

Answer 152

A When the fetus is Rh positive or the Rh status of the fetus is unknown, termination of a pregnancy from any cause presents a situation in which an Rh-negative patient should receive RhIg. A minidose is used if the pregnancy is terminated in the first trimester.

Answer 153

A The negative Kleihauer-Betke test result confirms that the positive reaction of the woman’s RBCs with anti-D at the IAT phase is not the result of fetal–maternal bleeding. The woman is weak D positive and, therefore, requires molecular testing to discern if she is a candidate for RhIg. Weak D types 1, 2, 3, and 4 do not make anti-D and do not require RhIg prophylaxis.

Answer 154

B An O-negative mother who gives birth to an A-positive baby and has no anti-D formed from a previous pregnancy would be a candidate for RhIg. A mother who already has active anti-D or a mother who gives birth to an Rh-negative baby is not a candidate for RhIg. Anti-D formation via active immunization typically has a titer greater than 4, compared with passive administration of anti-D, which has a titer less than 4.

Answer 155

D To calculate the number of vials of RhIg to infuse, divide 40 by 2,000, and multiply by 5,000. This gives the estimated total blood volume of the mother in milliliters. Divide this number by 30 to obtain the number of doses. When the number to the right of the decimal point is less than 5, round down, and add one dose of RhIg. Conversely, when the number to the right of the decimal point is 5 or greater, round up, and add one dose of RhIg. In this example, the number of doses is 3.3. Rounding down and adding one vial gives an answer of four vials

Answer 156

B Kernicterus occurs because of high levels of unconjugated bilirubin. High levels of this pigment cross into the central nervous system, causing brain damage to the infant.

Answer 157

B Plasmapheresis removes excess anti-E from the mother and provides a temporary solution to the problem until the fetus is mature enough to be delivered. The procedure may need to be performed several times, depending on how quickly and how high the levels of anti-E rise. Administration of RhIg would not contribute to solving this problem caused by anti-E. Intrauterine transfusion would not be performed before week 20 and would be considered only if there is evidence of severe hemolytic disease.

Answer 158

B ABO (forward) and Rh are required. An antibody screen using either the neonatal serum or maternal serum is required. Crossmatching is necessary as long as maternal antibody persists in the infant’s blood.

Answer 159

A Either AB-negative or O-negative RBCs may be given to an AB-positive baby because both types are ABO compatible and lack the D antigen.

Answer 160

B An antibody screen is not performed routinely on a cord blood sample because a baby does not make antibodies until about 6 months of age. Any antibodies detected in a cord blood sample come from the mother.

Answer 161

B The most common reason an Rh-negative woman has a positive antibody screen is because of previously receiving RhIg or passive anti-D.

Answer 162

D Anti-A,B is an IgG antibody and can cross the placenta and attach to infant cells. It is known as a single entity as opposed to separate antibodies. Anti-D would not be the cause because this is the first pregnancy. Anti-K is not the cause because there is no history of alloantibodies or past transfusions.

Answer 163

D Blood banks operate by strict standard operating procedures. These include decisions about which products are supplied from the blood bank. Although B may also be a solution, D is the best answer because the patient’s physician can communicate with the pathologist once he or she receives this information from the nurse.

Answer 164

C Pools of up to 16 donors are tested by nucleic acid amplification technology. If the pool is reactive, samples from each individual donor are tested. Pooled donors may also be screened for Zika virus using nucleic acid amplification

Answer 165

C According to the AABB standards, NAT testing is required for viruses HIV-1, HCV, HBV, Zika, and WNV.

Answer 166

A According to the FDA guidelines, donors who retest as NAT HIV nonreactive and negative for anti-HIV-1,2 are eligible to donate in their re-entry program.

Answer 167

B The first viral marker of hepatitis B to appear in the serum once exposed is the HBSAg, which appears in as few as 5 days (5–28 days) after exposure.

Answer 168

C Anti-HBs is indicative of immunity or vaccination to hepatitis B. Anti-HBc IgM occurs in the early stage of infection; anti-HBc IgG follows and may persist for years following infection. HBsAg is a marker of HBV infection, not immunity.

Answer 169

Daratumumab (Darzalex) is a monoclonal antibody directed against CD38, which shows enhanced expression on multiple myeloma tumor cells. Because CD38 is also expressed on RBCs, all screening cells will be positive. The serological workup appears as a warm autoantibody that cannot be resolved with adsorptions and often necessitates the transfusion of least incompatible RBCs.

Answer 170

A This is a case of a false-positive screening test result (RPR). The confirmatory test for treponemal antibodies was negative. The donor unit is acceptable and may be used to prepare blood components.

Answer 171

B The recipient’s physician should be notified by the medical director to ascertain the current health status of the recipient, if known, and determine what treatment, if any, the recipient should receive

Answer 172

B Testing of donor blood for antibodies to CMV is not required. However, testing may be done on units intended for transfusion to low-birth-weight infants born to seronegative mothers or units used for intrauterine transfusion; units intended for immunocompromised patients who are seronegative; prospective transplant recipients who are seronegative; or transplant recipients who have received a seronegative organ. Leukocyte-reduced RBCs carry a reduced risk of transmitting CMV and are recommended for such patients when CMV testing has not been performed on donor units. The prevalence of anti-CMV in the population ranges from 40% to 90%.

Answer 173

A According to current FDA and CDC criteria, a sample is defined as anti-HIV positive if at least two of the following bands are present on Western blot: p24, gp41, and/or GP120/160.

Answer 174

A The blood typing result demonstrates A antigen on the RBCs and anti-B in serum. The secretor result reveals A antigen in the saliva. A antigen neutralized anti-A, preventing agglutination when A1 cells were added. Each blood type (except a Bombay phenotype) contains some H antigen; therefore, H antigen in saliva would be bound by anti-H reagent. No agglutination would occur when O cells are added.

Answer 175

C The mixed-field reaction with anti-A suggests a subgroup of A, most likely A3. The reverse grouping shows weak agglutination with A1 cells, indicating anti-A1. A positive reaction with anti-A,B would help to differentiate an A subgroup from group O. If A2 cells are not agglutinated by patient serum, the result would indicate the presence of anti-A1. If the patient’s serum agglutinates A2 cells, then an alloantibody or autoantibody should be considered.

Answer 176

B The scenario showed an antibody in the patient serum directed toward M antigen, and the M antigen happened to be on the A1 cells in reverse grouping. To solve this problem, find A1 cells negative for M antigen or enzyme treat the A1 cells to resolve the ABO discrepancy.

Answer 177

C In the case of an AB-positive person, a saline control must be run in forward grouping to obtain a negative reaction; this will ensure agglutination is specific in the other reactions.

Answer 178

.C The most likely genotype is R1R1.The possibilities are DCe/DCe or DCe/dCe, which translates to R1R1 or R1h’. The former is more common.

Answer 179

C Because the patient has never been transfused or pregnant previously, she probably has not formed any atypical antibodies. Because she is Rh negative she would have received a dose of RhIg at 28 weeks (antenatal dose) if her prenatal antibody screen had been negative. Although technical error cannot be ruled out, it is far less likely than RhIg administration to be the cause.

Answer 180

A An enzyme panel would help to distinguish between anti-Jka (reaction enhanced) and anti-Fya (destroyed). Anti-D, however, would also be enhanced and may mask reactions that may distinguish another antibody. A select panel of cells negative for D may help to reveal an additional antibody or antibodies.

Answer 181

A Lowering the pH will actually enhance reactivity of anti-M. Prewarming (anti-M is a cold-reacting antibody), cold adsorption with homozygous M cells, and testing the serum with enzyme-treated RBCs (destroys M antigens) are all techniques to remove reactivity of anti-M.

Answer 182

C AET denatures Kell antigens and has no effect on Kidd antibodies. Because the detection of Kidd antibodies is subject to dosage effect, selection of cells homozygous for the Jka antigen (and longer incubation) would help to detect the presence of the corresponding antibody. Enzyme-treated RBCs would also react more strongly in the presence of Kidd antibodies.

Answer 183

D Because RBCs contain variable amounts of I antigen, reactions with anti-I often vary in agglutination strength. However, because this patient was recently transfused, the variation in reaction strength may be the result of an antibody mixture. Although autoadsorption would remove anti-I, this procedure does not confirm the antibody specificity and can result in removal of other antibodies, as well. Cord blood cells express primarily i antigen with very little I antigen. Anti-I would react weakly or negatively with cord RBCs. ZZAP removes IgG antibodies from RBCs. Because anti-I is IgM, the use of ZZAP would not be of value.

Answer 184

C Lewis antibodies are usually not clinically significant but may interfere with testing for clinically significant antibodies. Lewis antibodies are most easily removed by neutralizing them with soluble Lewis substance. Lewis antigens are secreted into saliva and plasma and are adsorbed onto RBCs. Leb substance is made by adding an L-fucose to both the terminal and next to last sugar residue on the type 1 precursor chain. This requires the Le, H, and Se genes. Because some samples of anti-Leb react only with group O or A2 RBCs, neutralization is best achieved if the saliva comes from a person who is group O.

Answer 185

B The automated analyzer would result the patient with a weak D phenotype as Rh negative, and if blood were needed, the patient would receive Rh-negative blood.

Answer 186

B The baby forward types as an A, and the mother is O negative. It is possible that anti- A,B from the mother is attaching to the baby’s RBCs, causing a positive DAT result. In the presence of a positive DAT, a weak test for D is not valid. Therefore, the baby’s Rh type is unknown, and the mother would be a candidate for RhIg.

Answer 187

A If the RBCs show a positive DAT result, then IgG antibody has coated incompatible, antigen-positive RBCs. If screening cells and panel cells show missing or weak reactions, most of the antibody is on the RBCs and would need to be eluted before it can be detected. An elution procedure followed by a panel performed on the eluate would help to identify the antibody.

Answer 188

A All screening cells and all units are positive at both 37°C and the IAT phase. This indicates the possibility of a high-frequency alloantibody or a warm autoantibody. An autocontrol would help make this distinction. A positive autocontrol indicates an autoantibody is present; a negative autocontrol and positive screen cells indicate an alloantibody. A DAT would be performed to determine if an antibody has coated the patient’s RBCs and is directed against screening cells and donor cells.

Answer 189

B A patient with a history of a significant antibody, such as anti-Jkb, must receive blood that has been completely crossmatched and is negative for the corresponding antigen; otherwise, an anamnestic reaction may occur with subsequent lysis of donor cells.

Answer 190

C In this situation, an allogeneic adsorption must be performed to adsorb out the autoantibody and leave potential alloantibodies in the patient’s serum that will need to be identified before transfusion of blood to the patient. An autoadsorption cannot be performed because any alloantibodies would be absorbed by circulating donor cells present from the previous month.

Answer 191

C Anti-P1 is a cold-reacting antibody. Warming the plasma at 37°C will dissipate the antibody, preventing its reactivity with P1 antigen on the A1 cells.

Answer 192

20. C In this case, the maternal anti-A,B is probably coating the infant’s B cells, causing a positive DAT and jaundice. Anti-A,B from an O person is a single entity that cannot be separated. It is IgG and can cross the placenta. This antibody may attach to A, B, or AB RBCs.