Pine Woods Screening Services, LLC

PWSS, LLC. is now offering cutting-edge hair testing to screen for drugs of abuse. The PDT-90 Test gives an approximate 90 day history of any drug use using a few strands of hair.

This PDT-90 will find:

• marijuana
• cocaine (including Crack)
• Opiates (including Heroin, codeine, Morphine, Oxycodone, Hydrocodone and Hydromorphone)
• PCP
• Amphetamines (including Methamphetamine, Ecstasy, MDMA and MDEA)

*Also, an additional hair test can determine alcohol consumption for an approximate 90 day period.

Is there a risk that the results of a hair test can be affected by environmental contamination?

The lab we use employs several independent approaches which, in various combinations, rule out the possibility of a positive result from external contamination.

The first method involves extensive chemical washing of the hair specimen prior to screening, followed by analysis of the content of the wash. This wash analysis is a critical step to ensure that any contamination is effectively accounted for.

Additionally, the lab measures the presence of metabolites. If drugs were in the air or on a person’s hands and thereby got on a person’s hair from outside, the drug would be present as the drug substance itself, and not as certain metabolites or with metabolite/parent drug ratios which are known to be produced by ingestion.

The labs’ ability to distinguish and measure metabolites with its highly sensitive GC/MS/MS or LC/MS/MS equipment is one criteria used to eliminate the possibility of false positives from external contamination.

In addition, any positive internal contamination (e.g., from passive inhalation or even poppy seed consumption) is distinguished from deliberate drug use by setting GC/MS/MS or LC/MS/MS cut-off levels above those which can be produced by passive internal exposure. Studies have shown that the combination of extensive washing, metabolite analysis, and proper cut-off levels are necessary to avoid false positives due to external contamination.

How much hair is needed?

The labs’ standard screen, along with GC/MS/MS or LC/MS/MS confirmation, usually requires a cosmetically undetectable lock of hair preferably snipped from the back of the head, just below the crown. In general, the amount needed is the thickness of a shoelace tip. Hair analysis methods used by other laboratories may require significantly more hair.