Results: anti-A 4+, anti-B 0, anti-D 4+, and the control for the high-protein anti-D reagent 3+. What should be done?

Treat the D type as invalid and investigate

Report the patient as group A, D-negative

Report the patient as group A, D-positive

Repeat only the ABO grouping with anti-A1

A patient with cold agglutinin disease types: anti-A 4+, anti-B 2+; A1 cells 0, B cells 4+; autocontrol 2+ at room temperature. What should be done next?

Wash the cells in warm saline and retype them

Retype the cells using Dolichos biflorus lectin

Report group AB and give group AB plasma

Add group AB serum to the cells

A patient with acute myeloid leukemia, previously group A and never transfused, now types: anti-A 1+ mixed field, anti-B 0; A1 cells 0, B cells 4+. The most likely cause is:

Weakened A antigen from the leukemia

Recent transfusion of group O red cells

A patient with multiple myeloma has extra reactions in the reverse grouping, and the clumps look like stacks of coins under the microscope. How is this resolved?

Saline replacement in the reverse grouping

Retyping the cells with anti-A1 lectin

Heating the plasma to 56 °C before testing

Adding more reagent antisera to the forward tubes

A group A patient received 3 units of group O red cells yesterday. Today the cells show mixed-field agglutination with anti-A. This shows:

Two cell populations: patient and donor

An acquired B antigen from infection

A weak A subgroup inherited from a parent

Antibody-coated cells giving false reactions

Routine tests: ABO/Rh grouping

15 ASCP MLS practice questions on Routine tests: ABO/Rh grouping, part of Blood Banking. The first 15 are below; the first 5 with answers and explanations (tap Show answer after you have chosen), the rest in Learn with a free account.

Question 1 · Hard
Results: anti-A 4+, anti-B 0, anti-D 4+, and the control for the high-protein anti-D reagent 3+. What should be done?
1. AReport the patient as group A, D-negative
2. BReport the patient as group A, D-positive
3. CTreat the D type as invalid and investigate
4. DRepeat only the ABO grouping with anti-A1
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Answer: C · Treat the D type as invalid and investigate
A positive control means something other than anti-D is clumping the cells, so the D result cannot be interpreted. With high-protein reagents, IgG-coated cells (a positive DAT) or strong cold autoagglutinins commonly cause this. The cells are tested with a DAT, washed in warm saline, and retyped with a low-protein monoclonal anti-D and its control, or after removing the IgG. Until it is resolved, D-negative red cells are given if transfusion is needed.
- A: The control result means the D type is unknown, not negative.
- B: A positive control invalidates the anti-D reaction.
- D: The ABO grouping is not the problem; the D typing is.
Question 2 · Hard
A patient with cold agglutinin disease types: anti-A 4+, anti-B 2+; A1 cells 0, B cells 4+; autocontrol 2+ at room temperature. What should be done next?
1. ARetype the cells using Dolichos biflorus lectin
2. BWash the cells in warm saline and retype them
3. CReport group AB and give group AB plasma
4. DAdd group AB serum to the cells
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Answer: B · Wash the cells in warm saline and retype them
The cold autoantibody coats the patient's cells and makes them clump in the anti-B tube, giving a false positive. The reverse grouping shows anti-B, so the patient is really group A. Washing the cells in warm (37 °C) saline, or treating them with DTT to break up IgM, removes the autoagglutination before retyping. The discrepancy must be resolved before the group is reported.
- A: Dolichos tests for A1 and does not address the false anti-B reaction.
- C: The plasma contains anti-B, so the patient cannot be group AB.
- D: AB serum does not remove the cold autoantibody from the cells.
Question 3 · Hard
A patient with acute myeloid leukemia, previously group A and never transfused, now types: anti-A 1+ mixed field, anti-B 0; A1 cells 0, B cells 4+. The most likely cause is:
1. AAn inherited A3 subgroup
2. BRecent transfusion of group O red cells
3. CWeakened A antigen from the leukemia
4. DAcquired B antigen
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Answer: C · Weakened A antigen from the leukemia
Leukemia, especially acute myeloid leukemia, can reduce A or B transferase in the malignant clone, weakening the antigen, sometimes with a mixed field. Earlier records show a normal group A, so the change is acquired, not inherited. The antigen often returns to normal in remission. The reverse grouping and history confirm group A.
- A: An inherited subgroup would not appear after an earlier normal group A typing.
- B: The patient has never been transfused.
- D: Acquired B changes the reaction with anti-B, which is negative here.
Question 4 · Medium
A patient with multiple myeloma has extra reactions in the reverse grouping, and the clumps look like stacks of coins under the microscope. How is this resolved?
1. ARetyping the cells with anti-A1 lectin
2. BHeating the plasma to 56 °C before testing
3. CAdding more reagent antisera to the forward tubes
4. DSaline replacement in the reverse grouping
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Answer: D · Saline replacement in the reverse grouping
High plasma protein levels, as in myeloma, make red cells stack into rouleaux that look like agglutination. Replacing the plasma with saline after centrifugation disperses rouleaux, while true agglutination remains. Rouleaux mainly affects tests that use the patient's plasma, such as the reverse grouping and antibody screen. Washing the patient's cells keeps it out of the forward grouping.
- A: Anti-A1 lectin separates A1 from A2 cells; it does not remove rouleaux.
- B: Heating to 56 °C inactivates complement but does not stop protein-induced rouleaux.
- C: More antisera would not change reactions caused by the patient's plasma proteins.
Question 5 · Medium
A group A patient received 3 units of group O red cells yesterday. Today the cells show mixed-field agglutination with anti-A. This shows:
1. ATwo cell populations: patient and donor
2. BAn acquired B antigen from infection
3. CA weak A subgroup inherited from a parent
4. DAntibody-coated cells giving false reactions
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Answer: A · Two cell populations: patient and donor
The patient's group A cells agglutinate while the transfused group O cells do not, giving clumps among free cells. Mixed-field reactions are expected after transfusion of a different ABO group, after an ABO-mismatched stem cell transplant, and in rare chimeras. The transfusion history is checked before a subgroup is suspected. The mixed field fades as the donor cells are removed over weeks to months.
- B: Acquired B affects reactions with anti-B, not anti-A.
- C: A subgroup would not appear suddenly after a transfusion.
- D: Antibody coating causes false positives with all reagents, not a mixed field with anti-A only.
Question 6 · Hard
Results: anti-A 4+, anti-B 4+; A1 cells 2+, B cells 0; autocontrol 0. The cells do not react with Dolichos biflorus lectin. The most likely interpretation is:
1. AGroup AB with rouleaux
2. BGroup AB with a cold autoantibody
3. CGroup A2B with anti-A1
4. DGroup B with a weak A subgroup
Answer and explanation in LearnFree account
Question 7 · Medium
Unwashed cord blood cells give weak, nonspecific clumping in every tube of the forward grouping. What is the likely cause and fix?
1. ACold agglutinins; incubate the tubes at 4 °C
2. BWeak cord antigens; treat the cord cells with enzymes
3. CWharton's jelly; wash the cord cells thoroughly
4. DMaternal anti-A,B; do a reverse grouping
Answer and explanation in LearnFree account
Question 8 · Hard
A group B patient types: anti-A 0, anti-B 4+; A1 cells 4+, B cells 1+. The antibody screen shows anti-M reacting at room temperature. How is the reverse grouping resolved?
1. AReport the patient as group AB
2. BRepeat it with M-negative B cells
3. CReport the patient as group O
4. DRepeat the forward grouping with anti-A,B
Answer and explanation in LearnFree account
Question 9 · Medium
A bleeding patient needs red cells now, but the forward and reverse ABO groupings do not agree. Until the discrepancy is resolved, the patient should receive:
1. ARed cells matching the reverse grouping
2. BGroup O red cells and group AB plasma
3. CRed cells matching the forward grouping
4. DNo blood until the discrepancy is resolved
Answer and explanation in LearnFree account
Question 10 · Hard
A healthy 26-year-old woman, a fraternal twin, is a first-time blood donor. She has never been transfused, pregnant or given a transplant, and her blood count is normal. Results: anti-A 2+ mixed field, anti-B 0, anti-A,B 2+ mixed field, anti-D 2+ mixed field; A1 cells 0, B cells 4+; antibody screen negative. Saliva studies show that she is a secretor with H substance only. A new sample collected the next week gives the same results. The most likely explanation is:
1. AA3 subgroup of group A
2. BTwin blood group chimerism
3. CAend subgroup of group A
4. DWeakened A antigen from leukemia
Answer and explanation in LearnFree account
Question 11 · Hard
A 74-year-old man with colon cancer and gram-negative sepsis typed group A two years ago and has not been transfused since. Given today's results shown, the most likely cause of the discrepancy is:
Figure: MedExams
1. AAcquired B antigen
2. BA weak B subgroup
3. CT activation
4. DTwin chimerism
Answer and explanation in LearnFree account
Question 12 · Medium
An 86-year-old man with chronic lymphocytic leukemia and low immunoglobulin levels has the grouping results shown. What should be done to resolve the discrepancy?
Figure: MedExams
1. AIncubate the reverse tubes at room temperature
2. BWash his red cells with warm saline
3. CUse saline replacement in the reverse tubes
4. DTest his red cells with anti-A1 lectin
Answer and explanation in LearnFree account
Question 13 · Easy
Refer to the tube grouping results shown. The patient's ABO and D type is:
Figure: MedExams
1. AA, D-negative
2. BAB, D-positive
3. CAB, D-negative
4. DO, D-negative
Answer and explanation in LearnFree account
Question 14 · Medium
A first-time blood donor's red cells give the D typing results shown. How should the unit be labeled?
Figure: MedExams
1. ALabel it partial D
2. BLabel it D-positive
3. CLabel it D-negative
4. DLabel it Rh undetermined
Answer and explanation in LearnFree account
Question 15 · Easy
A patient's red cells agglutinate with anti-B but not with anti-A. The patient's serum agglutinates A1 cells but not B cells. What is the ABO group?
1. AGroup O
2. BGroup AB
3. CGroup A
4. DGroup B
Answer and explanation in LearnFree account

Routine tests: ABO/Rh grouping

Results: anti-A 4+, anti-B 0, anti-D 4+, and the control for the high-protein anti-D reagent 3+. What should be done?

A patient with cold agglutinin disease types: anti-A 4+, anti-B 2+; A1 cells 0, B cells 4+; autocontrol 2+ at room temperature. What should be done next?

A patient with acute myeloid leukemia, previously group A and never transfused, now types: anti-A 1+ mixed field, anti-B 0; A1 cells 0, B cells 4+. The most likely cause is:

A patient with multiple myeloma has extra reactions in the reverse grouping, and the clumps look like stacks of coins under the microscope. How is this resolved?

A group A patient received 3 units of group O red cells yesterday. Today the cells show mixed-field agglutination with anti-A. This shows:

Results: anti-A 4+, anti-B 4+; A1 cells 2+, B cells 0; autocontrol 0. The cells do not react with Dolichos biflorus lectin. The most likely interpretation is:

Unwashed cord blood cells give weak, nonspecific clumping in every tube of the forward grouping. What is the likely cause and fix?

A group B patient types: anti-A 0, anti-B 4+; A1 cells 4+, B cells 1+. The antibody screen shows anti-M reacting at room temperature. How is the reverse grouping resolved?

A bleeding patient needs red cells now, but the forward and reverse ABO groupings do not agree. Until the discrepancy is resolved, the patient should receive:

A 74-year-old man with colon cancer and gram-negative sepsis typed group A two years ago and has not been transfused since. Given today's results shown, the most likely cause of the discrepancy is:

An 86-year-old man with chronic lymphocytic leukemia and low immunoglobulin levels has the grouping results shown. What should be done to resolve the discrepancy?

Refer to the tube grouping results shown. The patient's ABO and D type is:

A first-time blood donor's red cells give the D typing results shown. How should the unit be labeled?

A patient's red cells agglutinate with anti-B but not with anti-A. The patient's serum agglutinates A1 cells but not B cells. What is the ABO group?