Testing for illegal substances through hair is the most sensitive method for identifying drug use by an individual. Hair drug testing provides comprehensive information about current drug use and goes back 90 days of one's history of drug usage. This test is administered by collector that is not allowing individual to alter or tamper the specimen.

For hair drug testing the specimen can be taken from either person's head or the body. Hair drug testing is ideal for individuals with at least two inches of trimmable hair.