ASCP Transfusion Medicine 3

Question 1

Massive transfusion protocol (MTP) typically uses a ratio of plasma:platelets:red blood cells of approximately:

Accepted Answer

1:1:1

Answer

1:1:10

Answer

3:2:1

Answer

1:0:6

Question 2

The most common immune cause of platelet refractoriness is:

Accepted Answer

HLA alloimmunization (anti-HLA class I antibodies)

Answer

ABO incompatibility

Answer

Anti-platelet-specific antibodies (anti-HPA)

Answer

Anti-D alloimmunization

Question 3

A patient with a history of heparin-induced thrombocytopenia (HIT) requires cardiac surgery. The most appropriate anticoagulant approach is:

Accepted Answer

Use bivalirudin (direct thrombin inhibitor) or delay until PF4-heparin antibodies decline

Answer

Use low-molecular-weight heparin (LMWH) instead

Answer

Proceed with unfractionated heparin — HIT history is not a contraindication

Answer

Use warfarin during bypass

Question 4

Neonatal alloimmune thrombocytopenia (NAIT) most commonly involves antibodies against which platelet antigen?

Accepted Answer

Human platelet antigen 1a (HPA-1a)

Answer

HLA class II antigens

Answer

ABO antigens on platelets

Answer

Glycoprotein IV (CD36)

Question 5

Gel (column agglutination) technology in blood banking works by:

Accepted Answer

Centrifuging red cells through a gel matrix — agglutinated cells are trapped at the top while unagglutinated cells pellet at the bottom

Answer

Using electrical current to detect red cell agglutination

Answer

Measuring turbidity changes in a liquid medium

Answer

Directly measuring hemoglobin released from lysed cells

Question 6

An ABO discrepancy is found where the patient forward types as group A but the reverse grouping shows unexpected anti-A reactivity. This is best described as:

Accepted Answer

ABO discrepancy requiring investigation — likely a weak A subgroup (A2) with anti-A1

Answer

Rouleaux formation artifact

Answer

Bombay phenotype

Answer

Technical error only