Keratin, the primary component of nails, can trap drug metabolites as they are incorporated during nail growth. Laboratory analysis of nail clippings can detect these metabolites, providing a detection window significantly longer than that of urine or blood tests. Results are typically reported in picograms per milligram (pg/mg), a unit of measurement indicating the concentration of a specific substance within the nail sample. For example, a result of 50 pg/mg for a specific substance indicates 50 picograms of that substance are present for every milligram of nail. This quantification allows for a more precise assessment of drug use history.
This method offers several advantages. Its wider detection window, often extending back several months, provides a more comprehensive view of past substance use compared to other methods. The stability of keratin also makes nail samples less susceptible to adulteration or environmental degradation. This increased reliability has led to wider adoption of nail analysis in various settings, including workplace drug testing, forensic investigations, and clinical monitoring of prescribed medications.
