Hair Sample

What do you currently know about hair testing? Hair drug testing is an effective way to evaluate long-term patterns of use.  Some employers choose to use hair testing because the collection process is relatively noninvasive and it is challenging to cheat a hair drug test. While hair tests can detect long-term drug use, they can’t detect recent use and there is a longer processing time required to get results. Hair drug testing is the only testing method available that provides up to a 90-day drug use history. However, these tests cannot pinpoint the exact date of drug use because hair growth rates can vary widely among different people. Although hair samples undergo a two-step testing process, they are not 100 percent accurate. Factors that can affect the concentration of drug metabolites present in a hair sample include:

  • The structure of drug compounds
  • The quantity of drugs a person has consumed
  • How much a person sweats
  • The amount of melanin (dark hair pigment) in a person’s hair — certain drugs bind more readily to melanin
  • Bleaching or coloring the hair


The use of typical styling products and shampoos should not affect the test results. In 2015, researchers at the Friends Research Institute in Baltimore, Maryland, conducted a study examining the effectiveness of hair follicle drug tests. The researchers compared self-reported drug use with hair follicle test results from 360 adults at risk for moderate drug use. According to the results of the study, hair follicle drug testing correctly identified:

  •          52.3 percent of people who reported recent marijuana use
  •          65.2 percent of people who reported recent cocaine use
  •          24.2 percent of people who reported recent amphetamine use
  •         2.9 percent of people who reported recent Opioid use


Are you interested in looking at adding hair testing to your drug testing program? Give us a call; we are always happy to help! 1.800.452.0030 ext. 203.