Hair Drug Tests


Hair follicle drug tests can detect drug use over a much longer period of time compared to urine tests. 

RaBu Diagnostics's standard hair follicle test looks for drugs in the past 5 to 90 days, whereas a urine test typically only detects drug use for up to a week. Hair tests should be used to examine someone for repetitious drug use over an extended period of time. Hair testing is a newer methodology, but is becoming more and more popular among employers and court systems, due to the extended look-back period that it offers. 


Pros and Cons of Hair Drug Tests

  • Longer look back than urine test (up to 90 days or more)
  • Very difficult to cheat (we cut the hair right from the person’s head or body)
  • A single usage of a drug in the prior 90 day period tends to not be picked up in the hair
  • If person has no head or body hair, then the test can’t be done
  • If a person used drugs in the immediate past (the most recent 5 days), it will not have had time to grow out of the hair follicle into the strand of hair that we cut and test; therefore, if immediate usage is suspected, choose a urine drug test instead


Hair Follicle Drug Testing Basics

A small amount of hair (approximately 120 strands) are cut and sent to our lab for analysis.  We need at least 1.5 inches of hair to do this test, and we can use hair from the head, chest, leg, or armpit.  Some of our clinics only perform the head hair test, while others do body hair as well. The hair is cut by one of our technicians at a clinic; you should not bring pre-cut hair with you. 

When someone ingests drugs, the drugs or their metabolites get deposited into the hair follicle. Despite the name of this test, we do not actually test the follicle, or “root”  itself.  Rather, when the hair grows out of the follicle, the evidence of drug use remains intact.  In fact, it stays in the hair forever. We only test the first inch and a half, equating approximately to a 90 day history of drug use. There is some debate about the lookback period for body hair, though our lab estimates it at 90 days, as well. 


Can a Hair Test be Beat?

External chemicals or shampoos do not work to change the ability of this test to detect drug usage. Environmental exposure (such as second hand marijuana smoke) does not cause a positive hair test.


Hair Drug Tests Can Screen for Several Substances

  • Heroin
  • Codeine, and Morphine
  • Cocaine
  • Marijuana
  • Amphetamines
  • Ecstasy
  • PCP (Angel Dust)
  • Hyrdrocodone and Oxycodone
  • Benzodiazapenes
  • Methadone
  • Barbiturates
  • Propoxyphene
  • Oxycontin
  • Demerol
  • Tramadol
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