ABPath Blood Banking and Transfusion 4

Question 1

The direct antiglobulin test (DAT) detects which of the following?

Accepted Answer

Antibody or complement bound to red cells in vivo

Answer

The DAT detects immunoglobulin or complement already coating red cells in vivo.

Question 2

In the ABO system, which individual is the universal plasma donor?

Accepted Answer

Group AB

Answer

Group AB plasma lacks anti-A and anti-B, making it the universal plasma donor.

Question 3

The Rh antigen most commonly implicated in hemolytic disease of the fetus and newborn is:

Accepted Answer

D

Answer

Anti-D remains the most clinically significant cause of severe HDFN.

Question 4

What is the purpose of Rh immune globulin (RhIG) administration in an RhD-negative pregnant woman?

Accepted Answer

To prevent maternal anti-D alloimmunization from fetal RhD-positive cells

Answer

RhIG prevents active immunization by clearing fetal RhD-positive cells before sensitization.

Question 5

A weak D phenotype is best explained by which molecular mechanism?

Accepted Answer

Reduced quantity of complete D antigen on the red cell

Answer

Weak D results from a reduced number of otherwise complete D antigen sites.

American Board of Pathology (ABPath) Practice Test