Last updated: November 27, 2023
A hair follicle drug test doesn’t actually require removing hair follicle specimens from under the test subject’s scalp. Any drug metabolites that stow away in the hair follicle begin growing out into the hair within a matter of a few days. The technician gathers the specimen by clipping strands of hair—about the same thickness as a #2 pencil—as close to the scalp as possible. They take the hair from a place that isn’t visible to others. Should the test subject have thin hair, the strands are gathered from several different areas so as not to be noticeable.
Employers have traditionally shied away from using the hair follicle drug test in the past. A big component of that fact is due to the cost of the test. Other than the blood test, most often reserved for post-accident drug testing, the hair test is the most costly. However, once word got around that this test affords employers the ability to discover habitual use, they began to take a second look at this method of employee drug testing.
It’s true that, currently, using the hair follicle test to detect employees who use drugs is more costly. However, it affords benefits that are causing even small business owners to consider switching over to this drug testing method. There is one huge difference between the hair test and other drug testing methods though. It’s the ability for employers to determine how often someone used drugs for ninety days prior to the specimen collection.
In fact, some trucking companies now ask their drivers to submit to two drug tests. The urine drug test is required by the Department of Transportation (DOT). If the company doesn’t use it, it will become out of compliance. Some companies request a hair specimen for drug testing as well because the test detects drug use over a longer period of time. It’s been reported that upon learning that a hair specimen for drug testing is expected in addition to the DOT drug test, some potential drivers terminate their interview immediately and leave.
Another benefit of these tests is the impossibility of tampering with the specimen in an attempt to mask drug use. Moreover, the subject is always in full view of the technician collecting the specimen. This eliminates the possibility of someone trying to substitute someone else’s hair in place of their own.
Employers are free to test for whatever drugs they choose, but, typically, employers choose a ready-made test that consists of the following panels:
The hair test doesn’t detect current impairment. It takes between five and seven days for the drug metabolites to reach the hair follicle and grow out into the hair itself.
About the test
The test is so non-invasive that some employers choose to have it administered on-site rather than employees reporting to a testing facility or hospital setting. Hair drug testing kits can be purchased in-store or online. After collecting the specimens, the next step in the process is to mail them to the laboratory for analysis.
Styling products, hair dye, shampoos, and conditioners don’t have any effect on the outcome of the test. That’s because the drug metabolites that collect in the hair follicle actually grow out into the center of the hair shaft. They fuse with the hair and remain there permanently.
Theoretically, then, it would be possible to look back even farther than the common ninety-day period. Human hair grows at the rate of approximately 1/2 inch per month. No matter the length of a person’s hair, laboratory technicians cut the length of the specimens to a length of 1 1/2 inches making the standard look-back period about three months.
We mentioned above that the section of hair would be about the same diameter as a #2 pencil. That works out to approximately 100 to 120 strands of hair depending on its coarseness. Should a test subject have little or no hair growing on their head, the technician may gather the hair from various places on the body instead. Typically, techs wrap specimens in foil and secure them in an envelope.
A breakdown of results
Once at the laboratory, conducting an ELISA test determines a positive or negative result. If the ELISA test result is negative, the analysis is complete. It stands as proof that the individual has not used drugs within the past 90 days.
If the ELISA test is positive, additional testing of the specimen is required. It both confirms the positive result and determines the type of drug detected in the specimen. The second test, known as the GC/MS, is widely used for confirming positive drug test results. It guards against outside influences, such as certain foods or medications, from causing a false-positive result.
In rare instances, test results come up as inconclusive. The cause usually traces back to a testing procedure not being followed correctly. Usually, the test can be repeated using the same specimen. On occasion, however, there are cases of another specimen being required to complete the drug test.
The analysis is completed using a very specific set of standards, thereby, ensuring accuracy. Additionally, all specimens are washed and tested for environmental contamination that could possibly influence the end result.
Benefits outweigh cost
The ability to look over a 90-day period for drug use is the major draw for employers who choose to use the hair follicle drug test to screen employees. Even though it is currently more costly to use this test method, that may not always be the case. If employers continue to make the switch from urine testing to hair testing, it makes sense that the costs of the two may grow closer to the same.
The test is considered the least invasive employee drug test because it literally entails snipping a small group of hairs, 100 or so, near the scalp using a pair of scissors. You can’t mask drugs in the hair because the drug metabolites become a part of it as they grow out into the center of the hair shaft. And, lastly, the risk of tampering with a specimen disappears entirely because the test subject is in constant view.
In the long run, the hair test may be far more valuable than first thought by many employers. Are you one of them?