Hair Follicle Testing
Extend Detection Timelines
While a common urine drug test works to detect recent drug use (usually up to 72 hours prior to collection), hair follicle tests can reach up to three months further into the past. Similar to urine, drug metabolites are stored in hair follicles, but for much longer, providing a useful substance use history to employers.
While not as common as urine tests, hair follicle drug tests can be an important part of any screening program aimed to reduce substance-related issues in the workplace.
While not 100 percent accurate (as few things are), hair samples can reliably determine past drug use. However, due to varying hair growth rates, exact dates of consumption can not be pinpointed.
The concentration of drug metabolites in a given hair sample can be influenced by a number of factors including:
- Amount and frequency of substance use
- How much a person sweats
- Amount of dark pigment (melanin) in the hair
- Presence of bleach or coloring in the hair
Hair samples don’t need to be collected from the head. They can also be sourced from the armpit or face. The hair must be at least 0.5 inches in length.
By and large, hair follicle tests are more costly than urine tests.
While hair follicle tests provide insights further into the past, they aren’t too effective in detecting recent drug use (it may take up to 7 days). It’s just the opposite with urine tests. Because of this, many organizations implement drug screening programs that utilize urine tests and hair follicle tests together in order to cover all the bases.
Hair tests are most commonly used in tandem with urine tests to meet more detailed drug screening requirements typical within legal, medical, and education industries as well as corporate settings. They are effective at detecting drug use up to 3 months prior to the date of collection, telling a more complete story than urine tests alone.
If you have more questions, feel free to reach out to us. Additionally, this article may provide some helpful insights as you try to determine the best course of action regarding your drug testing program.