Hair Follicle Drug Testing: How It Works & What It Detects

Hair follicle testing is a way to detect drug use. Drugs circulate through your bloodstream, nourishing your hair while it grows. Hair follicles trap a drug as it deposits into a follicle.

Hair Sampling

• Many hair follicle tests operate by requiring a sample of hair. About 1.5 inches of hair is necessary to confirm the presence of drug use, as indicated by the Drug Testing Network.

How it Works

• Hair follicle tests can provide results for various drugs.

  A lab analyzes a sample of up to 100 strands of hair taken to from the scalp to test for drugs. Testing can search for drugs such as marijuana, cocaine and opiates.

Confirmation

• Bleaching, washing or dyeing your hair will not get rid of the presence of drugs in your follicles. Being in a room with someone who is using drugs will not affect your test results. A positive result means that you tested positive for a specific drug.