CMT Blood Banking and Transfusion Medicine Flashcards

A group A patient recently received several group O red cell units. What reaction pattern is most likely with anti-A in forward typing?

Answer: Mixed-field agglutination

The patient's own group A cells agglutinate while the transfused group O cells do not, which produces mixed-field agglutination.

In reverse typing, a patient with multiple myeloma shows agglutination with both A1 and B cells, and it looks like stacked coins under the microscope. Which technique resolves this?

Answer: Saline replacement

Rouleaux disperses when the plasma is replaced with saline, while true agglutination stays.

Why do Lewis antibodies rarely cause hemolytic disease of the fetus and newborn?

Answer: They are mostly IgM, and Lewis antigens are poorly developed on fetal red cells

Lewis antibodies are mostly IgM and cannot cross the placenta, and newborn red cells express little Lewis antigen.

A donor's red cells are negative with anti-D at immediate spin but positive at the antiglobulin phase of weak D testing. How should the unit be labeled?

Answer: Rh-positive

Weak D donor units are labeled Rh-positive because they could immunize an Rh-negative recipient.

A patient's cells type as group O, but the serum agglutinates all group O screening cells strongly at room temperature, and anti-H lectin does not react. Which blood should be given?

Answer: Oh (Bombay) phenotype

Bombay (Oh) individuals make potent anti-H, which hemolyzes normal group O cells, so they can receive only Oh blood.

Which antibody is most often linked to delayed hemolytic transfusion reactions because its titer often falls below detectable levels?

Answer: Anti-Jka

Kidd antibodies are known for disappearing from detection and then returning quickly in an anamnestic response after re-exposure.

What is the minimum interval between standard allogeneic whole blood donations?

Answer: 56 days

Whole blood donors must wait at least 8 weeks (56 days), while double red cell donors wait 112 days.