What is the significance of hair in drug testing?

What is the significance of hair in drug testing?

• A. Drugs present in blood diffuse into hair, marking drug intake and allowing for a timeline of use.
• B. Hair reflects only current use within 24 hours.
• C. Hair testing replaces urinary testing for all drugs.
• D. Hair testing detects only synthetic drugs.

Answer: (A)

Hair testing works because drugs circulating in the blood during hair formation become trapped in the growing keratin of the hair shaft. As hair grows at about 1 centimeter per month, analyzing a strand and its segments can reveal a timeline of exposure over weeks to months, not just a single moment. This long-term record makes hair a useful alternative to detect patterns of use, but it’s not a replacement for all drugs in all situations and can be influenced by contamination, washing, hair color, and drug properties. It reflects both natural and synthetic substances, and is particularly valuable for establishing past use rather than immediate, within-the-last-24-hours status.

Hair testing works because drugs circulating in the blood during hair formation become trapped in the growing keratin of the hair shaft. As hair grows at about 1 centimeter per month, analyzing a strand and its segments can reveal a timeline of exposure over weeks to months, not just a single moment. This long-term record makes hair a useful alternative to detect patterns of use, but it’s not a replacement for all drugs in all situations and can be influenced by contamination, washing, hair color, and drug properties. It reflects both natural and synthetic substances, and is particularly valuable for establishing past use rather than immediate, within-the-last-24-hours status.