HAIR ANALYSIS FOR DRUGS OF ABUSE: FINAL REPORT

• NCJ Number: 146672
• Author(s): G L Henderson; M R Harkey; R Jones
• Date Published: 1993
• Length: 69 pages
• Grant Number(s): 90-NIJ-CX-0012
• Sponsoring Agency: National Institute of Justice (NIJ); National Institute on Drug Abuse; US Dept of Justice NIJ Pub
• Sale Source: National Institute of Justice/; NCJRS Photocopy Services
• Publication Format: Document
• Publication Type: Report (Technical)
• Language: English
• Country: United States of America

Annotation

The studies reported here show that hair analysis with a sensitive and specific method such as gas chromatography/mass spectrometry (GC/MS) can detect cocaine use or exposure.

Abstract

Isotopically labeled cocaine was administered intravenously or intranasally to 25 human volunteers under controlled clinical conditions. Sequential blood and sweat were collected for up to 3 days, and hair samples were collected for up to 10 months. All samples were then analyzed by GC/MS. The use of isotopically labeled cocaine allowed researchers to distinguish between the administered drug and any cocaine used by the subjects either before or during the study. Hair analysis that used GC/MS was a sensitive means for detecting cocaine ingestion. The threshold dose using this method was estimated to be approximately 25-35 mg drug IV. This is the amount of drug typically found in a single "line" of cocaine. In a series of in vitro experiments, control (drug-free) hair was exposed to cocaine in an aqueous solution or in vapor form ("crack smoke"). Hair could be extensively contaminated through this external exposure. Washing with various solutions (detergents and organic solvents) or treatment with cosmetic agents (bleach, perming, or straightening solutions) removed most, but not all, of the externally applied drug. The researchers advise that the mechanisms for cocaine incorporation into hair are more complex than previously thought. Thus, currently there is not the scientific evidence necessary for hair analysis to determine either the time or amount of cocaine use. Because external contamination may be a source for evidentiary "false" positives for cocaine (i.e., drug is present but not due to ingestion), all hair testing procedures for cocaine must be designed to guard against any inadvertent contamination of the sample during collection or analysis and external contamination must be ruled out when interpreting hair analysis results. 19 figures, 17 tables, and 36 references