Sexual offences and forensic psychiatry: toluidine blue: 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.

Try it

Forensic Medicine · Sexual offences and forensic psychiatry: toluidine blue

Sample item

While examining a rape survivor, the doctor paints the posterior fourchette with a blue dye taken up by exposed nuclei, so that microscopic abrasions become visible. Which stain is this?

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

The answer and the reasoning

B. Toluidine blue

Toluidine blue is a nuclear stain that binds the nuclei exposed where the superficial keratin layer is lost, outlining microtears of the posterior fourchette and vestibule. It is used to detect minor genital injuries after sexual assault.

Option by option

  • A. Lugol's iodine

    Lugol's iodine stains glycogen in vaginal epithelium and does not outline nuclei.

  • B. Toluidine blue (correct)

    Correct. Toluidine blue outlines mucosal microtears.

  • C. Giemsa stain

    Giemsa is a blood film and cytology stain, not applied to living tissue.

  • D. Silver nitrate

    Silver nitrate is a caustic agent, not a diagnostic stain.

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.

More Forensic Medicine questions

Questions about this Forensic Medicine question

What is the answer to this Forensic Medicine question?

The best answer is B, Toluidine blue. Toluidine blue is a nuclear stain that binds the nuclei exposed where the superficial keratin layer is lost, outlining microtears of the posterior fourchette and vestibule.

Why is "Lugol's iodine" not the answer?

Lugol's iodine stains glycogen in vaginal epithelium and does not outline nuclei.

Why is "Giemsa stain" not the answer?

Giemsa is a blood film and cytology stain, not applied to living tissue.

Why is "Silver nitrate" not the answer?

Silver nitrate is a caustic agent, not a diagnostic stain.

What concept does this question test?

It tests Sexual offences and forensic psychiatry: toluidine blue in Forensic Medicine. It is used to detect minor genital injuries after sexual assault.

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 Sexual offences and forensic psychiatry: toluidine blue?

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.