A man suspected of chronic arsenic poisoning undergoes forensic investigation. Mees' lines are found in his nails. Which is the MOST specific method for detecting chronic arsenic exposure in a living person?

• A 24-hour urinary arsenic excretion
• B Blood arsenic level
• C Reinsch test on urine
• D Hair and nail arsenic analysis ✓

Explanation

Hair and nail arsenic analysis provides a chronological record of exposure as arsenic binds irreversibly to keratin-rich tissues. Segmental analysis of hair can date the exposure timeline (approximately 1 cm per month growth). Blood arsenic reflects only acute or very recent exposure because it clears rapidly. Urinary arsenic is the best marker for current or recent exposure. The Reinsch test is a qualitative screening test for heavy metals (arsenic, antimony, bismuth, mercury) in urine, not a quantitative chronic-exposure marker.

Reference: The Essentials of Forensic Medicine and Toxicology (Narayan Reddy), 34th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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