Blood Bank Module 3-Blood Banking
Procedures Study Guide Exam and
Actual Answers 2025-2026 Updated.
Cord Blood Workup - Answer 7mL sample is collected-red top; 5mL sample-EDTA tube
held for a minimum of 4 days @1-6 degrees unless mother is group O or D negative then
forward ABO type, Rh and DAT are performed
sample is washed 5 times to remove Wharton's jelly
Inspection of Donor Blood - Answer should be inspected prior to crossmatch and prior to
release for administration for abnormal color, clots, hemolysis, and cloudy plasma
Treatment of an Incompletely Clotted Specimen - Answer Heparing therapy or excessive
fibrinolytic activity can cause problems
blood centrifuged before completely clotted can produce fibrrin strands or clots entrapping
RBCs and can appear to be a reaction
the specimen is treated with thrombin to cause faster clotting or serum can be agitated with
glass beads at 37 degrees
also protamine sulfate can be added to neutralize the heparin
A,B,H,Le^a and Le^b:Saliva Testing - Answer can be useful in determining some blood type
discrepancies
people who secrete A,B,H, and Le^a in their saliva are called secretors-Se/Se or Se/se
these water-soluble substances can be detected by hemagglutination inhibition when present in
saliva
Absorption of Cold Autoagglutinis - Answer cold-reacting autoantibodies can interferer with
the identificaiton of alloantibodies in a patient' serum
absorption of a patient's serum with their own red blood cells at 4 degrees can remove these
cold autoantibodies from the serum allowing the detection of the presence of any other
antibodies which were being masked
Absorption of Warm Autoagglutinins - Answer these react at body temperature, are already
attached to the person's RBCs so the RBCs have to be treated with a proteolytic enzyme to
remove the warm autoantibody
Alloantibody Titration - Answer utilizes serial dilutions of the patient's serum to measure the
concentration of the antibody presence in the serum
,Crossmatching: The Prewarm Technique - Answer bypasses the phase at which cold-reacting
antibodies react
ensures that if agglutination occurs, it is due to a significant antibody reacting at 37 degrees and
not a cold-reacting insignificant antibody
from collection throughout procedure the specimen must be kept at 37 degrees
Donath-Lansteiner Screening Test - Answer positive test is indicative of Paroxysmal Cold
Hemoglobinuria-PCH
PCH is an IgG autoanti-P and know as the Donath-Lansteiner antibody
It is a potent hemolysin and also a biphasic hemolysin
test requires patients serum mixed with their cells be incubated at 4 degrees where compliment
coats the cells and then at 37 degrees when the cells will hemolyze
Elution Techniques - Answer purpose is to elute any antibody attached to RBCs
this gives an eluate
several types that use physical means-heat, freeze-thaw, solvents-chloroform, methylene, and
lowering pH-glycine acid
Rossette Test for Detection for Fetomaternal Hemorrhage - Answer most frequently used
test for screening for HDN
detects fetal D positive cells in circulation of a D negative postpartum mother
Hemoglobin F Determination by Acid Eluction-Kleihauer-Betke Method - Answer Blood
smears are made, fixed with ethyl alcohol, treated with an acid buffer, and then stained
fetals cells, contain hgb F, remain pink while maternal cells appear as ghost cells due to the
removal of their hgb by the acid buffer
Compatibility Testing - Answer 1. Compatibility testing involves all the steps in the
identification and testing of a donor unit and a proposed recipient's blood
2. Crossmatching is part of compatibility testing
-Involves mixing donor RBCs and recipient serum or plasma
-No agglutination or hemolysis indicates compatibility
-Agglutination or hemolysis indicates incompatibility
-do NOT crossmatch plasma or platelets, only RBCs
Purpose of Crossmatching - Answer 1. Crossmatching:
-Serves as a double check of ABO errors
,-Provides a second means of detecting antibodies
2. According to the AABB Standards, crossmatching:
"shall use methods that demonstrate ABO incompatibility and clinically significant antibodies to
red cell antigens and shall include an antiglobulin phase"
Serologic Crossmatching: IS CROSSMATCHING - Answer 1. IS crossmatching is performed
when the recipient has no evidence of an antibody
-In the current sample OR
-In the historical record
2. Recipient serum and donor RBC suspension are mixed and immediately centrifuged
3. Fulfills AABB standards for detecting ABO incompatibility
Serologic Crossmatching: ANTIGLOBULIN TEST - Answer 1. All phases (IS, 37° C, antihuman
globulin [AHG]) are performed if the patient demonstrates a clinically significant antibody
-In the current sample OR
-In the historical record
2. If the patient has autoantibody, autoadsorbed serum may be used
Crossmatching: Unexpected Incompatibilities in Immediate-Spin Crossmatch
Problem: ABO PHENOTYPING ERRORS - Answer -Causes: patient identification error, sample
labeling error
-Resolutions: repeat ABO testing, redraw patient
Crossmatching: Unexpected Incompatibilities in Immediate-Spin Crossmatch
Problem: UNEXPECTED ANTIBODIES - Answer -Causes: cold alloantibody (M, P1), anti A1 in
A2 patient, cold autoantibody (I, IH)
-Resolutions: test panel cells, test A2 cells, determine clinical significance
Computer Crossmatching - Answer -Makes a final check of the ABO compatibility in the
selection of units instead of a serologic IS procedure
, -The recipient must not have an antibody (or antibodies) in the current sample or have a history
of antibodies
-Bar codes are used to provide another measure of safety
Limitations in Crossmatching - Answer 1. An acceptable crossmatch does not guarantee a
successful transfusion:
-Adverse transfusion reactions may still occur
-A negative antibody screen does not guarantee that the recipient does not have significant
antibodies
-A compatible crossmatch does not guarantee survival of RBCs
Recipient Blood Sample - Answer 1. Patient identification and sample labeling: Patient and
sample information should have two independent identifiers (AABB Standards)
2. Sample collection tubes: Samples may be plasma or serum; purple or pink top (EDTA) tube is
plasma, red top tube is serum
3. Age of sample: The limit is 3 days if the patient has been recently transfused or is pregnant.
After 3 days, you must redraw a new specimen from the patient and retest EVERYTHING. Within
the 3 day period, only crossmatching must be retested.
4. Sample collection and appearance: Hemolyzed samples or samples contaminated with
intravenous fluids must be re-collected. Hemolysis indicates an antigen/antibody reaction.
Previous Records - Answer -Current blood ABO and D typing must be compared with results
performed over the past 12 months
-Previous records must also be consulted for any significant event related to testing or
transfusion
Repeat Testing of Donor Blood - Answer 1. Whole blood and RBCs must be re-typed to
confirm the correct ABO labeling:
-ABO testing is performed on all units
-D testing is performed only on D-negative units
-Weak D testing is not required
2. Records are kept for 5 years
Pretransfusion Testing - Answer 1. ABO and D typing: Discrepancies should be resolved
before transfusion
Procedures Study Guide Exam and
Actual Answers 2025-2026 Updated.
Cord Blood Workup - Answer 7mL sample is collected-red top; 5mL sample-EDTA tube
held for a minimum of 4 days @1-6 degrees unless mother is group O or D negative then
forward ABO type, Rh and DAT are performed
sample is washed 5 times to remove Wharton's jelly
Inspection of Donor Blood - Answer should be inspected prior to crossmatch and prior to
release for administration for abnormal color, clots, hemolysis, and cloudy plasma
Treatment of an Incompletely Clotted Specimen - Answer Heparing therapy or excessive
fibrinolytic activity can cause problems
blood centrifuged before completely clotted can produce fibrrin strands or clots entrapping
RBCs and can appear to be a reaction
the specimen is treated with thrombin to cause faster clotting or serum can be agitated with
glass beads at 37 degrees
also protamine sulfate can be added to neutralize the heparin
A,B,H,Le^a and Le^b:Saliva Testing - Answer can be useful in determining some blood type
discrepancies
people who secrete A,B,H, and Le^a in their saliva are called secretors-Se/Se or Se/se
these water-soluble substances can be detected by hemagglutination inhibition when present in
saliva
Absorption of Cold Autoagglutinis - Answer cold-reacting autoantibodies can interferer with
the identificaiton of alloantibodies in a patient' serum
absorption of a patient's serum with their own red blood cells at 4 degrees can remove these
cold autoantibodies from the serum allowing the detection of the presence of any other
antibodies which were being masked
Absorption of Warm Autoagglutinins - Answer these react at body temperature, are already
attached to the person's RBCs so the RBCs have to be treated with a proteolytic enzyme to
remove the warm autoantibody
Alloantibody Titration - Answer utilizes serial dilutions of the patient's serum to measure the
concentration of the antibody presence in the serum
,Crossmatching: The Prewarm Technique - Answer bypasses the phase at which cold-reacting
antibodies react
ensures that if agglutination occurs, it is due to a significant antibody reacting at 37 degrees and
not a cold-reacting insignificant antibody
from collection throughout procedure the specimen must be kept at 37 degrees
Donath-Lansteiner Screening Test - Answer positive test is indicative of Paroxysmal Cold
Hemoglobinuria-PCH
PCH is an IgG autoanti-P and know as the Donath-Lansteiner antibody
It is a potent hemolysin and also a biphasic hemolysin
test requires patients serum mixed with their cells be incubated at 4 degrees where compliment
coats the cells and then at 37 degrees when the cells will hemolyze
Elution Techniques - Answer purpose is to elute any antibody attached to RBCs
this gives an eluate
several types that use physical means-heat, freeze-thaw, solvents-chloroform, methylene, and
lowering pH-glycine acid
Rossette Test for Detection for Fetomaternal Hemorrhage - Answer most frequently used
test for screening for HDN
detects fetal D positive cells in circulation of a D negative postpartum mother
Hemoglobin F Determination by Acid Eluction-Kleihauer-Betke Method - Answer Blood
smears are made, fixed with ethyl alcohol, treated with an acid buffer, and then stained
fetals cells, contain hgb F, remain pink while maternal cells appear as ghost cells due to the
removal of their hgb by the acid buffer
Compatibility Testing - Answer 1. Compatibility testing involves all the steps in the
identification and testing of a donor unit and a proposed recipient's blood
2. Crossmatching is part of compatibility testing
-Involves mixing donor RBCs and recipient serum or plasma
-No agglutination or hemolysis indicates compatibility
-Agglutination or hemolysis indicates incompatibility
-do NOT crossmatch plasma or platelets, only RBCs
Purpose of Crossmatching - Answer 1. Crossmatching:
-Serves as a double check of ABO errors
,-Provides a second means of detecting antibodies
2. According to the AABB Standards, crossmatching:
"shall use methods that demonstrate ABO incompatibility and clinically significant antibodies to
red cell antigens and shall include an antiglobulin phase"
Serologic Crossmatching: IS CROSSMATCHING - Answer 1. IS crossmatching is performed
when the recipient has no evidence of an antibody
-In the current sample OR
-In the historical record
2. Recipient serum and donor RBC suspension are mixed and immediately centrifuged
3. Fulfills AABB standards for detecting ABO incompatibility
Serologic Crossmatching: ANTIGLOBULIN TEST - Answer 1. All phases (IS, 37° C, antihuman
globulin [AHG]) are performed if the patient demonstrates a clinically significant antibody
-In the current sample OR
-In the historical record
2. If the patient has autoantibody, autoadsorbed serum may be used
Crossmatching: Unexpected Incompatibilities in Immediate-Spin Crossmatch
Problem: ABO PHENOTYPING ERRORS - Answer -Causes: patient identification error, sample
labeling error
-Resolutions: repeat ABO testing, redraw patient
Crossmatching: Unexpected Incompatibilities in Immediate-Spin Crossmatch
Problem: UNEXPECTED ANTIBODIES - Answer -Causes: cold alloantibody (M, P1), anti A1 in
A2 patient, cold autoantibody (I, IH)
-Resolutions: test panel cells, test A2 cells, determine clinical significance
Computer Crossmatching - Answer -Makes a final check of the ABO compatibility in the
selection of units instead of a serologic IS procedure
, -The recipient must not have an antibody (or antibodies) in the current sample or have a history
of antibodies
-Bar codes are used to provide another measure of safety
Limitations in Crossmatching - Answer 1. An acceptable crossmatch does not guarantee a
successful transfusion:
-Adverse transfusion reactions may still occur
-A negative antibody screen does not guarantee that the recipient does not have significant
antibodies
-A compatible crossmatch does not guarantee survival of RBCs
Recipient Blood Sample - Answer 1. Patient identification and sample labeling: Patient and
sample information should have two independent identifiers (AABB Standards)
2. Sample collection tubes: Samples may be plasma or serum; purple or pink top (EDTA) tube is
plasma, red top tube is serum
3. Age of sample: The limit is 3 days if the patient has been recently transfused or is pregnant.
After 3 days, you must redraw a new specimen from the patient and retest EVERYTHING. Within
the 3 day period, only crossmatching must be retested.
4. Sample collection and appearance: Hemolyzed samples or samples contaminated with
intravenous fluids must be re-collected. Hemolysis indicates an antigen/antibody reaction.
Previous Records - Answer -Current blood ABO and D typing must be compared with results
performed over the past 12 months
-Previous records must also be consulted for any significant event related to testing or
transfusion
Repeat Testing of Donor Blood - Answer 1. Whole blood and RBCs must be re-typed to
confirm the correct ABO labeling:
-ABO testing is performed on all units
-D testing is performed only on D-negative units
-Weak D testing is not required
2. Records are kept for 5 years
Pretransfusion Testing - Answer 1. ABO and D typing: Discrepancies should be resolved
before transfusion
