Blood and immunity: cross-matching: practice question

A Physiology 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.

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Physiology · Blood and immunity: cross-matching

Sample item

A patient is to receive a red cell transfusion. In the major cross-match, which two components are mixed?

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

The answer and the reasoning

A. Donor red cells with recipient serum

The major cross-match detects antibodies in the recipient's serum that could destroy the donor's red cells, which is the important risk. The minor cross-match, donor serum with recipient cells, is of little importance because donor plasma is diluted in the recipient.

Option by option

  • A. Donor red cells with recipient serum (correct)

    Correct. Recipient antibodies against donor red cells are the main transfusion risk.

  • B. Recipient red cells with recipient serum

    This is an autocontrol, which tests for autoantibodies and not donor compatibility.

  • C. Donor red cells with donor serum

    Mixing a donor's own cells with serum does not test compatibility with the recipient.

  • D. Donor serum with recipient red cells

    This is the minor cross-match, which is less important because donor plasma is diluted.

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.

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Questions about this Physiology question

What is the answer to this Physiology question?

The best answer is A, Donor red cells with recipient serum. The major cross-match detects antibodies in the recipient's serum that could destroy the donor's red cells, which is the important risk.

Why is "Recipient red cells with recipient serum" not the answer?

This is an autocontrol, which tests for autoantibodies and not donor compatibility.

Why is "Donor red cells with donor serum" not the answer?

Mixing a donor's own cells with serum does not test compatibility with the recipient.

Why is "Donor serum with recipient red cells" not the answer?

This is the minor cross-match, which is less important because donor plasma is diluted.

What concept does this question test?

It tests Blood and immunity: cross-matching in Physiology. The minor cross-match, donor serum with recipient cells, is of little importance because donor plasma is diluted in the recipient.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. 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 Blood and immunity: cross-matching?

For each system, sketch the key graph (pressure–volume loop, oxygen dissociation curve, nephron handling) and explain it aloud. Then use the flashcards and the other Physiology 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.