Haematology: fetomaternal haemorrhage test: 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.

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Pathology · Haematology: fetomaternal haemorrhage test

Sample item

An Rh-negative woman delivers an Rh-positive baby after a placental abruption. A large fetomaternal haemorrhage is suspected and the dose of anti-D immunoglobulin must be adjusted. Which test quantifies fetal red cells in the maternal circulation?

AKleihauer-Betke testBDirect Coombs testCOsmotic fragility testDIndirect Coombs test

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

The answer and the reasoning

A. Kleihauer-Betke test

The Kleihauer-Betke test uses acid elution: fetal haemoglobin resists elution and stains pink, while adult red cells appear as ghosts. Counting the fetal cells estimates the volume of fetomaternal haemorrhage and the anti-D dose. Flow cytometry for HbF is an alternative.

Option by option

A. Kleihauer-Betke test (correct)
Correct. Acid elution leaves HbF-containing fetal cells stained, allowing quantification.
B. Direct Coombs test
The direct Coombs test detects antibody on the baby's red cells.
C. Osmotic fragility test
Osmotic fragility testing is used for hereditary spherocytosis.
D. Indirect Coombs test
The indirect Coombs test detects free antibodies in serum, such as maternal anti-D, and does not count fetal cells.

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, Kleihauer-Betke test. The Kleihauer-Betke test uses acid elution: fetal haemoglobin resists elution and stains pink, while adult red cells appear as ghosts.

Why is "Direct Coombs test" not the answer?

The direct Coombs test detects antibody on the baby's red cells.

Why is "Osmotic fragility test" not the answer?

Osmotic fragility testing is used for hereditary spherocytosis.

Why is "Indirect Coombs test" not the answer?

The indirect Coombs test detects free antibodies in serum, such as maternal anti-D, and does not count fetal cells.

What concept does this question test?

It tests Haematology: fetomaternal haemorrhage test in Pathology. Counting the fetal cells estimates the volume of fetomaternal haemorrhage and the anti-D dose. Flow cytometry for HbF is an alternative.

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 Haematology: fetomaternal haemorrhage test?

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.