Thanatology: staining for early myocardial infarct: practice question

A Forensic Medicine 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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Forensic Medicine · Thanatology: staining for early myocardial infarct

Sample item

A man dies suddenly about six hours after the onset of chest pain, and the myocardium looks normal to the naked eye. Which simple bench test can show an early infarct?

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

The answer and the reasoning

A. Tetrazolium (TTC) staining; infarct stays pale

Dehydrogenase enzymes in viable myocardium reduce tetrazolium to a red formazan dye. An infarct loses these enzymes within hours, so the infarcted area remains unstained and pale against the brick-red normal muscle, even before changes are visible on routine staining.

Option by option

  • A. Tetrazolium (TTC) staining; infarct stays pale (correct)

    Correct. Viable muscle stains red with TTC and infarcted muscle remains pale.

  • B. Sudan III staining; infarct turns orange

    Sudan III stains fat and does not outline an infarct.

  • C. Congo red staining; infarct turns red

    Congo red stains amyloid and does not outline an infarct.

  • D. Perls' Prussian blue stain; infarct turns blue

    Perls' stain detects iron and does not identify an early infarct.

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 Forensic Medicine question

What is the answer to this Forensic Medicine question?

The best answer is A, Tetrazolium (TTC) staining; infarct stays pale. Dehydrogenase enzymes in viable myocardium reduce tetrazolium to a red formazan dye.

Why is "Sudan III staining; infarct turns orange" not the answer?

Sudan III stains fat and does not outline an infarct.

Why is "Congo red staining; infarct turns red" not the answer?

Congo red stains amyloid and does not outline an infarct.

Why is "Perls' Prussian blue stain; infarct turns blue" not the answer?

Perls' stain detects iron and does not identify an early infarct.

What concept does this question test?

It tests Thanatology: staining for early myocardial infarct in Forensic Medicine. An infarct loses these enzymes within hours, so the infarcted area remains unstained and pale against the brick-red normal muscle, even before changes are visible on routine staining.

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 Thanatology: staining for early myocardial infarct?

Learn postmortem changes with their timelines, and toxicology as poison, sign, test and antidote. Then use the flashcards and the other Forensic Medicine 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.