Why is hair analysis useful in drug testing?

Why is hair analysis useful in drug testing?

• A. Because drugs diffuse from blood into hair, enabling a timeline of use.
• B. Hair testing detects only alcohol.
• C. Hair testing replaces urinary testing for all drugs.
• D. Hair testing determines exact dosage amounts.

Answer: (A)

Hair analysis is useful because drugs that circulate in the blood become incorporated into the growing hair and become embedded in the keratin as the strand forms. Since hair grows at a steady rate, analyzing different segments can reveal a timeline of drug use over weeks to months, with newer segments reflecting more recent exposure and older segments showing earlier use. This provides a longer detection window than urine testing, which mainly indicates recent use. Hair analysis can detect a range of substances, not just alcohol, and can indicate patterns of use rather than a single dose. It does not give exact dosage amounts, and results can be influenced by hair type, cosmetic treatments, and external contamination, so interpretation must consider these factors.

Hair analysis is useful because drugs that circulate in the blood become incorporated into the growing hair and become embedded in the keratin as the strand forms. Since hair grows at a steady rate, analyzing different segments can reveal a timeline of drug use over weeks to months, with newer segments reflecting more recent exposure and older segments showing earlier use. This provides a longer detection window than urine testing, which mainly indicates recent use. Hair analysis can detect a range of substances, not just alcohol, and can indicate patterns of use rather than a single dose. It does not give exact dosage amounts, and results can be influenced by hair type, cosmetic treatments, and external contamination, so interpretation must consider these factors.