How is hair analysis performed in the laboratory?
Hair analysis is performed by mirroring the federal forensic Substance Abuse and Mental Health Services Administration (SAMHSA) employment drug testing guidelines as closely as possible for a solid sample. Urine, of course, comes to us in liquid form. Hair must go through additional extraction procedures in order to release the drugs from the hair before testing, thus part of the increased cost.

The sample is received in the secured hair preparation area to be verified for complete chain of custody, adequate sample volume, and computer data entry. The sample is cut and weighed. Once the sample has been cut into very small pieces, it is then mixed to create as homogeneous a sample as possible. An internal chain of custody is created and a portion of the cuttings of each sample is sent to the hair-testing laboratory for screening.

Samples are washed to remove externally exposed drugs and to clean off interfering cosmetic materials.

The samples are prepared and the drugs are extracted into a liquid form. As with urine, the screening process is performed by immunoassay techniques, however, hair is screened using ELISA. Those samples, which test negative, are then reported as negative. If the screening process produces a suspected positive, a request is made from the hair preparation area to weigh out a new sample from the remainder of the original cuttings.

The second portion of the original cuttings is then subjected to washing, extraction, and confirmation testing by either gas chromatography mass spectrometry (GC/MS) or gas chromatography tandem mass spectrometry (GC/MS/MS). If the confirmation test is negative, there is no metabolite present, or the result is less than the cutoff, the sample is reported as negative. If the sample is positive above the cutoff for the drug and it’s metabolites, the laboratory reports the sample as positive.