Sexual offences: seminal fluid confirmation: 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 · Sexual offences: seminal fluid confirmation

Sample item

A man accused of rape had a vasectomy years ago, and a vaginal swab shows no spermatozoa on microscopy. Which test can still confirm seminal fluid?

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

The answer and the reasoning

A. Prostate-specific antigen (p30) immunoassay

Seminal plasma contains prostate-specific antigen (p30), produced by the prostate, so its detection confirms semen even when spermatozoa are absent, as in vasectomy or azoospermia. The other tests listed are tests for blood.

Option by option

  • A. Prostate-specific antigen (p30) immunoassay (correct)

    p30 is secreted by the prostate and persists when sperm are absent.

  • B. Takayama test

    The Takayama test produces pink feathery haemochromogen crystals from blood.

  • C. Teichmann haemin crystal test

    The Teichmann test produces haemin crystals from blood.

  • D. Kastle-Meyer test

    The Kastle-Meyer (phenolphthalein) test is a presumptive test for blood.

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, Prostate-specific antigen (p30) immunoassay. Seminal plasma contains prostate-specific antigen (p30), produced by the prostate, so its detection confirms semen even when spermatozoa are absent, as in vasectomy or azoospermia.

Why is "Takayama test" not the answer?

The Takayama test produces pink feathery haemochromogen crystals from blood.

Why is "Teichmann haemin crystal test" not the answer?

The Teichmann test produces haemin crystals from blood.

Why is "Kastle-Meyer test" not the answer?

The Kastle-Meyer (phenolphthalein) test is a presumptive test for blood.

What concept does this question test?

It tests Sexual offences: seminal fluid confirmation in Forensic Medicine. The other tests listed are tests for 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 Sexual offences: seminal fluid confirmation?

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.