Transfusion medicine: practice question

A Pathology question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

Try it

Pathology · Transfusion medicine

Sample item

On cell grouping, a patient's red cells show no agglutination with anti-A or anti-B. The serum agglutinates group A, group B and group O reagent cells. What is the most likely blood group?

ABombay phenotypeBGroup ABCRh-null phenotypeDGroup O

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

A. Bombay phenotype

Bombay (hh) individuals lack H antigen, so A and B antigens cannot be formed and the red cells type as O. Their serum contains anti-A, anti-B and anti-H, so it agglutinates even group O cells, and they can safely receive only Bombay blood.

Option by option

A. Bombay phenotype (correct)
Absent H antigen with anti-H in serum explains agglutination of group O cells.
B. Group AB
Group AB red cells would agglutinate with both anti-A and anti-B, and the serum would lack these antibodies.
C. Rh-null phenotype
Rh-null lacks Rh antigens and does not alter ABO grouping or cause anti-H.
D. Group O
True group O serum has anti-A and anti-B but no anti-H, so group O cells are not agglutinated.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

Questions about this Pathology question

What is the answer to this Pathology question?

The best answer is A, Bombay phenotype. Bombay (hh) individuals lack H antigen, so A and B antigens cannot be formed and the red cells type as O.

Why is "Group AB" not the answer?

Group AB red cells would agglutinate with both anti-A and anti-B, and the serum would lack these antibodies.

Why is "Rh-null phenotype" not the answer?

Rh-null lacks Rh antigens and does not alter ABO grouping or cause anti-H.

Why is "Group O" not the answer?

True group O serum has anti-A and anti-B but no anti-H, so group O cells are not agglutinated.

What concept does this question test?

It tests Transfusion medicine in Pathology. Their serum contains anti-A, anti-B and anti-H, so it agglutinates even group O cells, and they can safely receive only Bombay blood.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Transfusion medicine?

Learn each disease as a bundle: cause, key histology, markers, and the clinical hallmark. Then use the flashcards and the other Pathology questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.