BOC Blood Bank_2

c (Anti-Fya is an IgG antibody that reacts best at the AHG phase, does not react with enzyme-treated red cells, is capable of causing hemolytic disease of the newborn, and is not known to be an auto agglutinin.)

113) Anti-Fya is: a. usually a cold reactive agglutinin b. more reactive when tested with enzyme treated RBCs c. capable of causing hemolytic transfusion reactions d. often an auto agglutinin

a (Antibodies in the Kidd blood group system are IgG and react best at the antiglobulin phase. These antibodies are associated with delayed hemolytic transfusion reactions and reactivity can be enhanced by testing with enzyme pretreated cells.)

111) The antibodies of the Kidd blood group system: a. react best at the IAT b. are predominately IgM c. often cause allergic transfusion reactions d. do not generally react with antigen-positive, enzyme-treated RBC's

c (The Fya and Fyb antigens are sensitive to denaturation by proteolytic enzymes. Serum containing anti-Fya reacts with untreated Fy[a+] cells, but not with enzyme treated Fy[a+] cells.)

112) Proteolytic enzyme treatment of red cells usually destroys which antigen? a. Jka b. E c. Fya d. k

d (The Duffy glycoprotein on red cells is a receptor for the malarial parasite Plasmodium vivax. Red cells with the phenotype Fy[a-b-] are resistant to invasion by P vivax.)

114) Resistance to malaria is best associated with which of the following blood groups: a. Rh b. I/i c. P d. Duffy

a (Patients with severe hemophilia A may have spontaneous hemorrhages that are treated with Factor VIII concentrate.)

121) A blood component used in the treatment of hemophilia A is: a. Factor VIII concentrate b. FFP c. Platelets d. Whole Blood

d (HDFN is caused by maternal antibody crossing the placenta and destroying fetal antigen-positive red cells. Unlike ABO antibodies, which are naturally-occurring and can affect the first pregnancy, Rh antibodies are not produced until the mother has been exposed to Rh-positive red cells, usually during delivery of the first Rh-positive child Once immunized, subsequent pregnancies with Rh-positive infants are affected, usually with increasing severity.)

126) An obstetrical patient has had 3 previous pregnancies. her 1st baby was healthy, the 2nd was jaundiced at birth and required and exchange transfusion, while the 3rd was stillborn. Which of the following is the most likely cause: a. ABO incompatibility b. immune deficiency disease c. congenital spherocytic anemia d. Rh incompatibility

d (ABO HDFN is a mild disease, not usually requiring transfusion. It may occur in any pregnancy in which there is ABO incompatibility. High-titered IgG antibodies are more frequently seen in group O mothers than in A or B mothers.)

128) ABO hemolytic disease of the newborn: a. usually requires an exchange transfusion b. most often occurs in 1st born children c. frequently results in stillbirth d. is usually seen only in the newborn of group O mothers

d (HDFN is caused by maternal IgG antibodies. Outside the Rh system, the most clinically significant antibody for HDFN is anti-K. IgM antibodies do not cross the placenta.)

129) Which of the following antigens in most likely to be involved in HDFN. a. Lea b. P1 c. M d. Kell

a (ABO HDFN is a mild disease that may occur in any ABO-incompatible pregnancy, including the first, since the antibodies are naturally occurring Rh HDFN does not occur until the mother has become immunized. Once this happens, subsequent pregnancies may be quite severely affected. The DAT is typically weak or even negative in ABO HDFN, and strongly positive in Rh HDFN.)

130) ABO HDFN differs from Rh HDFN in that: a. Rh HDFN is clinically more severe that ABO HDFN b. the DAT test is weaker in Rh HDFN than ABO c. Rh HDFN occurs in the 1st pregnancy d. the mother's antibody screen is positive in ABO HDFN

a (ABO HDFN occurs most commonly in group A babies born to group O mothers and usually has a mild course. The DAT is typically weak or negative and jaundice develops 12-48 hours after birth. The mother and baby are both Rh-positive.)

132) A group A, Rh positive infant of a group O, Rh positive mother has a weakly positive DAT and moderately elevated bilirubin 12 hours after birth. the most likely cause is: a. ABO incompatibility b. Rh incompatibility c. blood group incompatibility due to and antibody to a low frequency antigen d. neonatal jaundice not associated with blood group

b (The change in optical density [absorbance] of amniotic fluid measured spectrophotometrically at 450 nm is calculated and plotted on the Liley graph according to the weeks gestation. The graph is divided into 3 zones, which predict the severity of HDFN and the need for intervention and treatment.)

134) The Liley method of predicting the severity of HDFN is based on the amniotic fluid: a. bilirubin concentration by standard methods b. change in optical density measured at 450nm c. Rh determination d. ratio of lecithin to sphingomyelin

c (A positive DAT on cord blood demonstrates the presence of maternal antibody coating the baby's red cells and indicates hemolytic disease of the newborn. Normal cord hemoglobin in newborns ranges from 14-20 g/L. A cord hemoglobin value of 10 g/L indicates anemia and supports the diagnosis of HDFN.)

135) These lab results were obtained on maternal and cord blood samples: Mother: A- baby: AB+ DAT 3+ cord hemoglobin 10 g/dL Does the baby have HDFN? a. no, as indicated by the cord hemoglobin b. yes, although the cord hemoglobin is normal, the DAT indicates HDFN c. yes, the DAT and cord hemoglobin level both support HDFN d. no, a diagnosis of HDN cannot be established without cord bilirubin levels

a (Blood for an exchange transfusion should lack the antigen to any maternal antibodies that have entered the infant's circulation and are reactive at 37 C or AHG.)

137) Which unit should be selected for exchange transfusion if the newborn is group A, Rh pos. and the mother is Group A, Rh pos. with anti-c? a. A, CDe/CDe b. A, cDE/cDE c. O, cde/cde d. A, cde/cde

a (Blood selected for exchange transfusion should be ABO-compatible with the mother and baby, and antigen-negative. Prenatal antibody titers above 16 or 32 are considered significant, and the condition of the fetus should be monitored.)

140) A blood specimen from a pregnant woman is found to be group B, Rh neg. and the serum contains anti-D with a titer of 512. What would be the most appropriate type of blood to have available for a possible exchange transfusion for her infant? a. O, Rh-neg b. O, Rh-pos c. B, Rh-neg d. B, Rh-pos

a (Blood selected for exchange transfusion should be antigen-negative and ABO compatible with the mother and baby. Red Blood Cells are usually less than 7 days old, CMV-, hemoglobin S-, and irradiated.)

141) Blood selected for exchange transfusion must: a. lack RBC antigens corresponding to maternal antibodies b. be <3 days old c. be the same Rh as the baby d. be ABO compatible with the father

c (For exchange transfusion, antigen- negative Red Blood Cells are typically resuspended in ABO-compatible thawed Fresh Frozen Plasma.)

142) When the main objective of an exchange transfusion is to remove the infant's antibody-sensitized RBCs and to control hyperbilirubinemia, the blood product of choice is ABO compatible: a. FFP b. RBCs washed c. RBC suspended in FFP d. heparinized RBCs

b (Blood selected for intrauterine transfusion and transfusion to premature infants should be irradiated to prevent graft-vs-host disease.)

143) To prevent graft vs host disease, RBCs prepared for infants who have received intrauterine transfusions should be: a. saline washed b. irradiated c. frozen and deglycerolized d. group-and Rh-compatible with the mother

b (The rosette test is a qualitative test. When enzyme-treated cells are used as indicator cells, a negative test [indicating there was not an excessive bleed] can have up to 1 rosette per 3 fields. The mother needs to receive 1 vial of RhIg for a normal bleed.)

147) What is the most appropriate interpretation for the laboratory data given below when an Rh-neg woman has an Rh-pos child? mother: 1 rosette/3 fields Positive Control.: 5 rosettes/3 fields Negative Control: no rosettes a. mother is not a candidate for RhIg b. mother need 1 vial RhIg c. mother need 2 vials RhIg d. the fetal maternal hemorrhage needs to be quantified

b (One dose of RhIg will protect the mother from a bleed of 30 mL. The bleed was 35 mL, 2 vials of RhIg will be needed)

150) The results of a Kleihauer-Butke stain indicate a fetomaternal hemorrhage of 35 mL of WHOLE BLOOD. How many vials of Rh immune globulin would be required. a. 1 b. 2 c. 3 d. 4

d (One vial of Rh immune globulin protects against a fetomaternal hemorrhage of 15 mL of red cells, or 30 mL of Whole Blood. Divide the volume of fetomaternal hemorrhage [35 mL] by 15; round down to 2, then add 1 extra vial = 3 vials total.)

151) A fetal maternal hemorrhage of 35 mL of fetal Rh-pos PACKED RBCs has been detected in an Rh-neg woman. How many vials of Rh immune globulin should be given a. 0 b. 1 c. 2 d. 3

c (RhIg should be given to nonimmunized D- females who are pregnant or have delivered a D+ infant.)

152) Criteria determining Rh immune globulin eligibility include: a. mother is Rh-pos b. mother is Rh-neg c. mother has not been previously immunized to the D antigen d. infant has a positive DAT

c (RhIg is of no benefit once a person has been actively immunized and has formed anti-D)

154) Rh immune globulin administration would not be indicated in an Rh-neg woman who has a: a. first trimester abortion b. husband who is Rh-pos c. anti-D titer of 1:4,096 d. mother having a positive DAT

b (The formula to calculate the percentage assumes the mother's blood volume as 5,000 mL. 0.003 x 5,000 mL = l5 mL.)

155) A Kleihauer-Betke stain of a postpartum blood film revealed 0.3 fetal cells. What is the estimated volume of the fetomaternal hemorrhage expressed as whole blood: a. 5 b. 15 c. 25 d. 35

b (The percentage of fetal cells/100, the mother's volume is assumed to be 5,000 mL. The percentage must be multiplied by 50 to determine total volume.)

156) Based upon Kleihauer-Betke test results, which of the following formulas is used to determine the volume of fetomaternal hemorrhage expressed in mL of whole blood. a. % of fetal cell present x 30 b. % of fetal cell present x 50 c. % of maternal cells x 30 d. % of maternal cells x 50

a (The rosette test is a sensitive method to detect FMH of 10 mL or more.)

158) The rosette test will detect a fetomaternal hemorrhage as small as: a. 10 mL b. 15 mL c. 20 mL d. 30 mL

d (Transfusion should generally be avoided except in cases of life-threatening anemia. A hemoglobin of 10.8 g/dL [108 g/L] is not life-threatening, especially if the patient is not actively bleeding.)

161) A 40 year old man with autoimmune hemolytic anemia due to anti-E has a hemoglobin level of 10.8 g/dL. This patient will most likely be treated with: a. whole blood b. RBCs c. FFP d. no transfusion

d (Bone marrow transplant patients are at risk for transfusion-associated graft-vs-host disease [TA-GVHD] and therefore should receive irradiated blood products.)

162) A patient in the immediate post bone marrow transplant period has a hematocrit of 21%. The red cell product of choice for this patient would be: a. packed b. saline washed c. micro aggregate filtered d. irradiated

b (HLA antigen typing is important to consider before organ transplantation.)

163) HLA antigen typing is important in screening for: a. ABO incompatibility b. a kidney donor c. Rh incompatibility d. a blood donor

a (Negative check cells means the results of tubes with the negative reactions are invalid. The reactivity of the check cells should be verified with anti-IgG since anti-E was detected, indicating the anti-IgG was reactive. All tests that were nonreactive with the check cells requires repeat test performance.)

165) Anti-E is identified in a panel at the antiglobulin phase. When check cells are added to the tubes no agglutination is seen. The most appropriate course of action would be to: a. quality control the AHG reagent and check cells and repeat the panel b. open a new vial of check cells for subsequent testing that day c. open a new vial of AHG for subsequent testing that day d. record the check cell reactions and report the antibody panel result

a (Samples must be labeled with 2 independent patient identifiers and the date of collection. This information should be identical to that on the patient's identification band and request.)

167) Which of the following represents an acceptably identified patient for sample collection and transfusion a. a handwritten band with patients name and hospital identification number is affixed to the patients leg b. the addressographed hospital band is taped to the patients bed c. an unbanded patient responds positively when his name is called d. the chart transported with the patient contains his armband not yet attached

c (A serological test to confirm the ABO on all RBC units and Rh on units labeled as Rh-negative must be performed prior to transfusion. Any errors in labeling must be reported to the collection facility.)

169) The following test results are noted for a unit of blood labeled group A, Rh-neg, anti-A 4+ anti-B 0 anti-D 3+ What should be done next? a. transfuse as a group A, Rh-neg b. transfuse as a group A, Rh-pos c. notify the collecting facility d. discard the unit

c (Samples must be labeled with 2 independent patient identifiers and the date of collection. This information should be identical to that on the patients identification band and request. There must be a mechanism to identify the phlebotomist, but initialing the sample tubes is not required.)

170) What information is essential on patient blood sample labels drawn for compatibility testing? a. biohazard sticker for AIDS patients b. patients room number c. unique patient medical # d. phlebotomist initials

b (Granulocytes must be compatible with recipient's plasma. Granulocyte products have an expiration of 24 hours.)

171) Granulocytes for transfusion should: a. be administered through a micro aggregate filter b. be ABO compatible with the recipients serum c. be infused within 72 hrs. of collection d. never be transfused to patients with a history of febrile transfusion reaction.

c (Because neonates are immunologically immature, alloimmunization to red cell antigens is very rare during the neonatal period. No crossmatching is required if the initial antibody screen performed with either the baby's or mother's plasma is negative.)

172) A neonate will be transfused for the first time with group O Red Blood Cells. Which of the following is appropriate compatibility testing? a. crossmatch with mothers serum b. crossmatch with baby's serum c. no crossmatch is necessary if initial plasma screening is negative d. no screening or crossmatching is necessary for neonates

b (A positive DAT will interfere with weak D testing, causing both the patient and control to demonstrate positive results. Any positive result in the control tube invalidates any results.)

173) A group B, Rh-neg patient has a positive DAT. Which of the following situations would occur? a. all major crossmatches would be incompatible b. the weak D test and control would be positive c. the antibody screen test would be positive d. the forward and reverse ABO groupings would not agree

c (Patients with multiple myeloma demonstrate rouleaux formation, which can cause the appearance of agglutination. If the cells are washed to remove residual plasma, and tests repeated, an accurate red cell typing is obtained. By performing a saline replacement with the reverse typing, true agglutination will remain when the cell buttons of the reverse cells are resuspended in saline.)

174) The following reaction were obtained: cells tested: anti-A = 4+| anti-B = 3+| anti-A,B = 4+ serum test: A1 cells = 2+ | B cells = 4+ The technologist washed the patients cells with saline and repeated the forward typing. A saline replacement technique was used with the reverse typing. the following results were obtained: cells tested: anti-A = 4+ | anti-B = 0 | anti-A,B = 4+ serum test: A1 cells = 0 | B cells = 4+ the results are consistent with: a. acquired immunodeficiency disease b. Bruton agammaglobulinemia c. multiple myeloma d. acquired "B" antigen

d (ABO immunoglobulins develop at approximately 3 months of age, attain adult levels by age 10, and may, but not always, decline in titer in the elderly)

175) What is the most likely cause of the following ABO discrepancy? Cells: anti-A = 0 | anti-B = 0 serum: A1 cells = 0 | B cells= 0 a. recent transfusion with group O blood b. antigen depression due to leukemia c. false-neg cell typing due to rouleaux d. obtained from the heel stick of a 2 month old baby

a (Tn is caused from a somatic mutation and the phenomenon is persistent. Resolution of the red cell typing can be performed with enzyme-treated patient cells, since Tn is denatured by enzymes. Although the reactivity with anti-A may be weak, testing with anti-A1 lectin gives strong reactivity, unlike subgroups of A, which are weakly reacting with anti-A and nonreactive with A1 lectin.)

177) Which of the following is characteristic of Tn polyagglutinable red cells? a. if group O, they may appear to have acquired a group A antigen b. they show strong reactions when the cells are enzyme treated c. they react with Arachis hypogaea lectin d. the polyagglutination is a transient condition

c (Mixed-field reactivity is a characteristic of the A3 subgroup. Transfusion history would be important to be sure it is not 2 cell populations.)

178) Mixed field agglutination encountered in ABO grouping with no history of transfusion would most likely be due to: a. Bombay phenotype (Oh) b. T activation c. A3 red cells d. positive IAT

b (Polyagglutination is a property of the cells. Most adult plasma agglutinate the cells due to naturally occurring antibodies directed towards the crypt antigens.)

179) Which of the following is a characteristic of polyagglutinable red cells? a. can be classified by reactivity with Ulex europaeus b. are agglutinated by most adult sera c. are always an acquired condition d. autocontrol is always positive

b (Although monoclonal anti-D react with most D+ red blood cells, cells with fewer antigen sites requires testing after the antiglobulin test. The test is referred to as a test for weak D.)

184) The test for weak D is performed by incubating patients red cells with: a. several different dilutions of anti-D serum b. anti-D serum followed by washing and antiglobulin serum c. anti-Du serum d. antiglobulin serum

d (Some subgroups of A are only recognized because of their lack of anti-A in the reverse typing. Often, the donors are confirmed as subgroups of A by an adsorption-elution technique.)

186) The following results were obtained when testing a sample from a 20 year old first time blood donor Forward: anti-A = 0 | anti-B = 0 Reverse: A1 cells = 0 | B cells = 3+ What is the most likely cause of this ABO discrepancy? a. loss of antigen due to disease b. acquired B C. phenotype Oh (Bombay) d. weak subgroup of A

c (The mom does not have the D gene. The father would have to have inherited one gene that produces D and another gene that does not produce D. The mom and dad both passed on genes that do not produce D.)

187) A mother is Rh neg. and the father is Rh pos. their baby is Rh neg. It may be concluded that: a. the father is homozygous for D b. the mother is heterozygous for D c. the father is heterozygous for D d. at least 1 of the 3 Rh typings must be incorrect

a (Some blood group antibodies, in the presence of their corresponding antigen and complement, activate the complement cascade and demonstrate in-vitro hemolysis.)

188) Some blood group antibodies characteristically hemolyze appropriate red cells in the presence of: a. complement b. anticoagulants c. preservatives d. penicillin

b (Agglutination at AHG phase indicates the presence of clinically significant antibody, indicating the need for antibody identification.)

189) Review the following schematic diagram: patient serum + reagent group O cells --> incubate --> read for agglutination --> wash --> add AHG --> agglutination observed --> ? The next step would be: a. add check cells as a confirmatory measure b. identify the cause of the agglutination c. perform an elution technique d. perform a DAT

b (Presence of agglutination at AHG phase with both screening cells and autocontrol is indicative of warm autoantibody.)

190) The following results were obtained in pre-transfusion testing: screen cell 1: @37 C = 0 | @IAT = 3+ screen cell 2: @37 C = 0 | @IAT = 3+ autocontrol: @37 C = 0 | @IAT = 3+ The most probable cause of these results are: a. rouleaux b. a warm autoantibody c. a cold autoantibody d. multiple alloantibodies

a (Presence of agglutination at AHG phase with screening cells and 2 out of 6 donor units indicates antibody in patient serum to antigen[s] on screening cells and donor cells. The presence of an autoantibody would most likely react with all cells, including the autologous control or DAT.)

191) A patient is typed as group O, Rh pos. and crossmatched with 6 units of blood. At the IAT phase of testing, both antibody screening cells and 2 crossmatched units are incompatible. What is the most likely cause of the incompatibility? a. recipient alloantibody b. recipient autoantibody c. donors have pos. DAT's d. rouleaux

c (Initial result was most likely a false-negative result due to the omission of patient serum. This would explain the initial negative result followed by the subsequent positive result.)

193) a patient received 2 units of RBCs and had a delayed transfusion reaction. Pretransfusion antibody screening records indicate no agglutination except after the addition of IgG sensitized cells. Repeat testing of the pretransfusion specimen detected an antibody at the antiglobulin phase. what is the most likely explanation for the original results? a. red cell were overwashed b. centrifuge time was prolonged c. patient's serum was omitted from the original test d. antiglobulin reagent was neutralized

b (The absence of agglutination at the AHG phase with screening cells and agglutination with one of 3 donor units is most likely due to an antibody to a low-incidence antigen.)

194) At the indirect antiglobulin phase of testing there is no agglutination between patient serum and screening cells. One of 3 donor units was incompatible. The most probable explanation for these findings is that the: a. patient has an antibody directed against a high incidence antigen b. patient has an antibody directed against a low incidence antigen c. donor has an antibody directed against donor cells d. donor has a positive antibody screen

d (The major crossmatch tests the recipient's plasma with donor's cells. This would detect any antibody in the recipient that would react with antigens on the donor's RBCs. If a patient were mistyped as a group O rather than group A, then group O cells would be selected for crossmatch and no incompatibility would be found.)

195) The major crossmatch will detect a (an): a. group A patient mistyped as a group O b. unexpected red cell antibody in the donor unit c. Rh-neg donor unit mislabeled as Rh-pos d. recipient antibody directed against antigens on the donor red cells

d (Since crossmatching is a test between the patient's plasma and donor's cells, any incompatibility is due to the donor's red cells. If a patient is negative for clinically significant antibodies to common antigens, an incompatible unit by the antiglobulin test is due to either a positive DAT on the donors red cells or the patient has an antibody to a low-incidence antigen that the donor's cells possess.)

197) Which of the following would most likely be responsible for an incompatible antiglobulin crossmatch? a recipients red cells possess a low frequency antigen b. anti-K antibody in donor serum c. recipients red cells are polyagglutinable d. donor red cells have a positive DAT

b (If a patient is negative for clinically significant antibodies, and a single crossmatch is incompatible, the incompatibility is either due to donor cells with a positive DAT or the patient has an antibody to a low-incidence antigen that the donor's cells possess.)

198) A reason why a patient's crossmatch may be incompatible while the antibody screen is negative is: a. the patient has an antibody against a high incidence antigen b. the incompatible donor unit has a positive DAT c. cold agglutinins are interfering in the crossmatch d. the patient's serum contains warm autoantibody

c (It a patient is negative tor clinically significant antibodies, and a single crossmatch is incompatible, the incompatibility is either due to donor cells with a positive DAT or the patient has an antibody to a low-incidence antigen that the donor's cells possess.)

199) A blood specimen types as A, Rh-pos with a negative antibody screen. 6 units of group A, Rh-pos RBCs were crossmatched and 1 unit was incompatible in the antiglobulin phase. The same result was obtained when the test was repeated. Which should be done first? a. repeat the ABO grouping on the incompatible unit using a more sensitive technique b. test a panel of red cells that possesses low incidence antigens c. perform a DAT on the donor unit d. obtain a new specimen and repeat the crossmatch

c (Emergency release of blood cannot use previous records. Blood typing must be performed on the current sample. In this case, group O Rh-negative is the best choice since there is evidence the patient is Rh-negative.)

200) During emergency situations when there is no time to determine ABO group and Rh type on a current sample for transfusion, the patient is known to be A, Rh-neg. the technologist should: a. refuse to release any blood until the patient's sample has been typed b. release A Rh-neg RBC's c. release O Rh-neg RBC's d. release O Rh-pos RBC's

b (When group specific units of Red Blood Cells are not available, group compatible units are selected. Since the patient is AB, group A would be selected to conserve group O units for group O patients. Rh-negative patients should receive Rh-negative units of red blood cells.)

201) A 29 year old male is hemorrhaging severely. He is AB, Rh-neg. 6 units of blood are required STAT. Of the following types available in the blood bank, which would be most preferable for crossmatch? a. AB, Rh-pos b. A, Rh-neg c. A, Rh-pos d. O, Rh-neg

a (This patient has an anti-A1, which eliminates A1B cells immediately. Rh-negative units should be conserved for Rh-negative patients when Rh-positive units are available. Selection of group B units provides compatible units quickly.)

202) A patient is group A2B, Rh-pos and has an antiglobulin reacting anti-A1 in his serum. He is in the operating room bleeding profusely and group A2B RBCs are not available. Which of the following blood types is first choice for crossmatching? a. B, Rh-pos b. B, Rh-neg c. A1B, Rh-pos d. O, Rh-neg

d (The strength of agglutination is dependent upon optimal antigen to antibody ratio. Excessive amount of antigen does not allow maximal uptake of antibody per red cell and therefore agglutination is negatively affected leading to weaker or negative results.)

203) A 10% red cell suspension in saline is used in a compatibility test. Which of the following would most likely occur? a. a false-positive result due to antigen excess b. a false-positive result due to the prozone phenomenon c. a false-negative result due to the prozone phenomenon d. a false-negative result due to antigen excess

a (Determining the patients phenotype allows focusing identification procedures toward antibodies the patient can develop.)

205) A patient received 4 units of blood 2 years previously and now has multiple antibodies. He has not been transfused since that time. It would be most helpful to: a. phenotype his cells to determine which additional alloantibodies may be produced b. recommend the use of directed donors, which are more likely to be compatible c. use proteolytic enzymes to destroy the "in vitro" activity of some of the antibodies d. freeze the patient's serum to use for antigen typing of compatible units

a (Warm autoantibodies often exhibit Rh specificity.)

206) Autoantibodies demonstrating blood group specificity in warm autoimmune hemolytic anemia are associated more often with which blood group system. a. Rh b. I c. P d. Duffy