The findings of the FBI study were extremely important as they validated that this wash procedure effectively removed contaminants from samples from people who could be legitimately
exposed to drugs in a workplace setting.
excreted in perspiration and subsequently deposited on the hair externally. To achieve accurate results, the hair testing laboratory must include in their process the ability to remove and account for any deposits on the external portion of the hair, evaluate if the procedure was effective, and then compare that against the cutoff levels. Normal hair may exhibit the presence of
drugs in two different areas: 1. On the Surface of the Hair: Surface contamination such as powder or vapor where the drug has not been exposed to moisture and therefore essentially just rests on the surface of the cuticle; this type of contami- nation can be removed readily by shorter washing methods. However, short wash procedures do not elimi- nate contamination in the presence of moisture, such as sweat, humidity, or bathing/shampooing that diffuses into the proteins of the cuticle but does not penetrate the cuticle.
2. On the Inside of the Hair: Drugs present inside the cortex of the hair de- posited in the follicle during ingestion that grows out into the shaſt of the hair above the scalp.
While most hair testing laboratories
may wash the hair samples as a standard practice, there are many different types of wash processes that exist offering a wide range of effectiveness in dealing with the issue of contamination.
FBI Validates
Effectiveness of Extended Wash Procedure In a recent landmark study conducted by the Federal Bureau of Investigation1
(FBI)
and later published in the Journal of Analyti- cal Toxicology, a wash process was validated when the study concluded that the extended wash and calculation described in conjunction with the measurement of metabolites would exclude false-positive results from environmental contact. Te
46 datia focus ●
FBI was looking to establish new reporting criteria and interpretation guidelines for forensic casework. Te findings of the FBI study were extremely important as they val- idated that this wash procedure effectively removed contaminants from samples from people who could be legitimately exposed to drugs in a workplace seting. Background and Key Points of the
FBI Study: ●
FBI conducted its study using the published method to find out whether cocaine users could be reliably distin- guished from those who are exposed to cocaine in their daily work—that is, real life exposure conditions.
●
FBI visited a well-known lab and con- ducted a study applying and validating the decontamination and calculation methods used. Te FBI publication cited previous studies published by the lab in 1993, 2002, 2004, and 2005.
●
FBI’s conclusion means that by us- ing this particular extended wash and kinetics calculation method, individuals legitimately exposed to cocaine in their daily work (atorneys prosecuting or defending drug charges, law enforcement officers handling drug evidence, crime laboratory employees, etc.) will not be at risk of being identified as cocaine users.
As a result of the study, the FBI has now adopted this non-proprietary wash protocol. Te extended wash procedure, cited by the FBI, was empirically developed over the last 30 years2
by studying washing
characteristics of laboratory-contaminated samples and thousands of drug-user samples. Tese results have been published and shared with the hair testing community since first being developed. Tis wash protocol requires multiple steps, including:
●
An extended wash procedure: Six steps with a three hour and 45 minute wash time, changing the wash solution between each step.
spring 2015
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