Drug Testing Information

Hair Drug Testing, also known as Follicle Testing, is the process of testing a person's hair for drug use. Hair follicle testing is more accurate than urine testing in regards to drugs such as cocaine, methamphetamines, opiates (including heroin), PCP and crack cocaine. This is because hair follicles keep evidence of drug use for up to 90 days, as long as the hair isn't cut. Many of these drugs would leave the bloodstream within a week and will not show up in a urinalysis test within a week or two. Marijuana however will show up in a urine drug test just as easily as in a hair follicle drug test if the marijuana was used within a few weeks or the person is obese.

Hair Follicle testing usually begins with a person visiting a lab and having strands of their hair collected. Approximately 50 strands of hair are generally needed for follicle testing, and each strand must be at least 1 inch in length. For this reason, many people (most notably, Britney Spears for example) have cut their hair in an effort to pass drug tests they normally wouldn't pass. In situations such as these, where no hair can be tested for the drug test, a urine test or saliva test may be ordered and may be more efficient.

Drugs can be detected in hair for much longer lengths of time than in urine. If a person uses a drug, and does not cut their hair, metabolites of that drug can be found in the strands of hair. Where in the strand, depends on how recently they used the drugs. The more time that has passed since they used the drug, the metabolites will be found farther down in the strand of hair. If the drug was used recently, then the metabolites will be found in the segments of the hair that are closer to the scalp. As the hair grows, those metabolites grow farther from the scalp. This is why many people who take court mandated hair follicle tests, are sometimes advised not to cut their hair too often.

Detection Time Frames For Hair Follicle Drug Testing (According to Labcorp)