The Flaws of Hair Follicle Drug Testing
At some point in your life you may have had to take a drug test as part of a pre-employment screening process, and the test was most likely a urine screen performed at the local health department or occupational services clinic. There are several different ways a person can be tested to determine if they have positive amounts of illegal substances (or forbidden substances) in their bodies, such as urine, blood, saliva, and hair follicle. The testing of a person's hair follicles for the presence of forbidden substances should be a highly contested and challenged process for one simple reason - everyone's hair grows at different rates and the growth rate can be affected by a multitude of things ranging from a person's diet to the shampoo they use to any medical conditions they have or prescribed medications they take. Also, hair growth rates vary based on ethnicity, as well.
On average, with no external influence, the human head hair grows at roughly a half-inch every month. Human hair (on the head) has certain phases during which it will grow, and this growth period varies from individual to individual (http://www.ehow.com/about_4587367_average-growth-rate-hair.html). To perform a drug test on a group of individuals who consumed the same forbidden substance at approximately the same time will return a wide spectrum of results, with none of the results being entirely accurate based on individual hair growth rates.
Products such as Rogaine will increase hair growth (thickness and length) because it speeds up cell division in hair follicles (http://www.breastcancer.org/treatment/planning/ask_expert/2001_08/question_02.jsp). Therefore, someone using Rogaine will have a faster growth rate than someone who isn't using the product. The natural aging process of hair, which is nothing more than dead protein cells after it has grown out of your skin, also can cause your hair growth cycle to slow down, while taking certain vitamins and mineral supplements can increase your hair growth rate (http://www.hairboutique.com/tips/tip214.htm). Even certain factors such as the climate in which you live can cause your hair growth rate to speed up or slow down, and stress (mental, emotional, or physical) can have a negative impact, as well.
As for drug testing using a hair follicle, most standardized drug screens that test hair will only test back to 90 days. This is contingent upon the type of test and the length of the hair sample, also. Detectable amounts of certain drugs end up in your hair follicles through your bloodstream, so anything that enters your bloodstream will eventually end up as part of your hair. In general, the hair sample is cut from the test subject's head as close to the scalp as possible and the one-and-a-half inches closest to the head are testing (which should be the past 90 days, if the hair grows the average half-inch per month).
How effective is a hair follicle test? Again, this should be part of the challenge to the accuracy of this type of testing. Hair tests can screen for cocaine, marijuana, opiates, methamphetamines, and PCP (the standard "screen" drugs as determined by federal guidelines), in general. For everything except marijuana (which is harder to identify in a hair follicle test), the tests are allegedly more accurate than urine screening in determining low level use over an extended period of time (http://www.ipassedmydrugtest.com/hair_drug_test_FAQ.asp). On it's face, this means that you would have to be a rather long-term regular user of a substance in order for it to be detectable in your hair. However, according to other sources, a weekend party of limited experimentation can provide a "positive" test result and you then find yourself labeled a drug user when, in fact, you're not.
Aside from the fact that everything ranging from stress to the climate to the foods you eat can have an impact on how fast or slow your hair grows, there are also no standardized laboratory testing procedures for hair follicle drug testing. It would seem that the "hit or miss" testing procedure can have "hit or miss" results which could unfairly cost someone a job (or more) simply due to lax testing or external stimuli such as the type of shampoo they use.
On the flipside, if you are a drug user or have used drugs in the past and you're worried about possibly failing a hair follicle drug test, there are quite a few very simple detoxification products available to ensure that you pass the test, and these products are much easier to use than some of the "pass your piss test" products (some of which require that you carry a bottle of synhthetic urine with you to the test site and pour it into the test cup). Detox shampoos are widely available over the internet and guarantee that you'll pass your hair follicle test. To use these products, you don't have to duct tape a bottle of warm urine under your arm or to the inside of your thigh and wear it all day in anticipation of your drug test...all you have to do is wash your hair with a different product when you shower before work! While trying to make it harder for people who use drugs to get jobs, they've actually made it easier because of the more simple methods of "detoxification" that are available for passing a hair test as opposed to passing a urine screen.
As I stated at the beginning of this article, hair follicle testing should be challenged by anyone who has to undergo it, for the simple reason that the disparity among hair growth rates is so vast that it simply cannot provide unbiased, objective results to determine if and when someone has ingested forbidden substances, and it certainly cannot provide even a "guess" as to the amount that was ingested (unlike urine screens, which can give an estimate of the quantity ingested based on the concentration of the substance in your urine).