The advantages of hair follicle drug testing include a longer detection period, lower chance of fooling one of these tests, and their relatively noninvasive nature. Testing the hair follicle is often thought of as more effective than urine or blood testing. While advantages of this form of drug testing can be numerous, there are some disadvantageous worth mentioning.
In the standard hair follicle drug testing, hairs are usually removed from the head, by cutting them as close to the scalp as possible. A number of hairs are collected and those with very short hair could lose several hundred at least in this process. It’s also possible to take hairs from the underarms, legs, or pubic area, but the last option, though still not invasive, may be embarrassing for people undergoing a test. These hairs are combined with chemicals that break them down, and if the test is positive, reveal evidence of usage of different drugs of abuse like marijuana, angel dust, amphetamines and methamphetamines and certain commonly prescribed drugs. The types of drugs screened for may depend on the extent or type of test performed.
While the average urine drug test will detect drug use up to 30 days prior to the test, one often-cited hair follicle drug testing advantage is that evaluation of hair may show drug use as far back as 90 days. Evidence of drug use continues to live in the hair shaft long after the body and blood eliminate signs of it, and finding this evidence could be very important in any situation where there is zero tolerance for legal or illegal drug use. As with any drug testing, people may have legitimate reasons to use certain drugs that are routinely screened for and should present evidence of prescriptions to show use isn’t illegal.
There are many urban legends about passing drug tests and even products that are sold that supposedly defeat hair follicle drug testing. Scientists find these recommendations or special shampoos don’t tend to work. Even chemically treated hair will still show evidence of drug use for up to three months prior. Another advantage listed is that cutting a few hairs, usually about 100, which is very minimal, is preferable to having to provide urine or blood samples. Additionally, concerns about things like second hand marijuana exposure are eliminated through hair testing; it does not to show up in the hair shaft.
The advantages of hair follicle drug testing have to be compared to the things detracting from it. First, this testing is much more expensive, and unlike urinalysis or blood tests, it may not detect drug use until five days after use occurs. It’s not the best choice to determine extremely recent use. It may pose problems for people with minimal hair, and some people are not happy having to provide body hair instead of head hair for a test. Testing is also more complex than urine tests and more difficult to perform at home.