Toxicology: hair analysis in chronic poisoning: 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 · Toxicology: hair analysis in chronic poisoning

Sample item

A woman is suspected of having been poisoned with arsenic in small doses over several months. Which sample best shows the timeline of her exposure?

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

The answer and the reasoning

C. Segmental analysis of scalp hair

Arsenic is incorporated into growing hair and nails, and hair grows about 1 cm per month. Analysis of successive segments gives a chronological record of intermittent exposure. Blood, gastric and spot urine samples show only recent exposure.

Option by option

  • A. A single serum sample

    A single serum sample reflects only recent exposure.

  • B. A gastric aspirate

    A gastric aspirate shows only what was swallowed in the last few hours.

  • C. Segmental analysis of scalp hair (correct)

    Correct. Hair segments record exposure over time because arsenic is deposited as the hair grows.

  • D. A spot urine sample

    A spot urine sample reflects recent excretion and not the historical pattern.

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 C, Segmental analysis of scalp hair. Arsenic is incorporated into growing hair and nails, and hair grows about 1 cm per month.

Why is "A single serum sample" not the answer?

A single serum sample reflects only recent exposure.

Why is "A gastric aspirate" not the answer?

A gastric aspirate shows only what was swallowed in the last few hours.

Why is "A spot urine sample" not the answer?

A spot urine sample reflects recent excretion and not the historical pattern.

What concept does this question test?

It tests Toxicology: hair analysis in chronic poisoning in Forensic Medicine. Analysis of successive segments gives a chronological record of intermittent exposure. Blood, gastric and spot urine samples show only recent exposure.

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 Toxicology: hair analysis in chronic poisoning?

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.