Drug Hair Testing Information

Drug testing of hair checks for usage of drugs such as tetrahydrocannabinol (marijuana), methamphetamine (ecstasy, crystal methadone), cocaine, phencyclidine (PCP) and opiates (heroin, codeine).

The Test

While hair drug testing tends to be more expensive than urine testing, the results are more conclusive. Additionally, hair testing can trace any drug use that took place over the previous three months. This test is performed in a laboratory setting.

The Sample

The appropriate sample size of hair required for testing is approximately 90 strands, about the thickness of a shoelace, cut as close to the scalp as possible. Typically, the most recently grown inch and a half of hair will be tested.

Body Hair vs. Head Hair

Though body hair grows slower than hair on the head, it can be used for drug testing. Because of the slow growth rate of body hair, if used as a sample, potential drug use can be traced over the previous year before the test.

Advantages

Hair drug testing is considered one of the most accurate tests for controlled substances. It is nearly impossible to tamper with the hair sample, thus strengthening the accuracy of results. Additionally, hair testing is one of the only ways to test drug use over an extended period of time.

Effectiveness

Hair drug testing has been shown to be more effective than other modes of testing. According to Erowid.org, in a recent study, out of 1,823 paired hair and urine samples, 57 urine samples tested positive for drugs of abuse, while 124 hair samples from the same group tested positive.

References

• Drug Testing Basics
• Hair Testing FAQs