INTERPRETING HAIR DRUG TEST RESULTS

Hair Drug Test Results Which Are Positive

The individual was most likely a chronic user of the drug detected during the time period indicated by the length of the hair.

Hair Drug Test Results Which Are Negative

The individual was not a chronic drug user during the time period indicated by the length of the hair.

There was not enough drug incorporated into the individual’s hair.  It should be noted that some drugs such as amphetamines and PCP are not efficiently incorporated into hair.

Hair drug testing detects the presence of amphetamines, opiates, cocaine, PCP and marijuana only.  The use of other drugs will not be detected.  Alcohol (ethanol) can not be detected in hair.

Evaluation of Time Period Represented in Hair

Hair grows at a rate of approximately 1 inch every two months.  Multiply the length of the individual’s hair by 2 to approximate the historical drug use record in months.

Hair Results vs. Urine Results

A negative hair drug test should never be used to refute the results of a positive urine drug test.  Hair drug testing is best at detecting chronic drug use whereas urine testing can detect a single drug use episode.

 Click here to view a sample hair test report