What is a Hair Follicle Drug Test?

N. Madison

A hair follicle drug test is used to screen a person for drug use. When an individual undergoes a hair follicle drug test, a sample of his hair is taken and checked for drug molecules and substances called metabolites. Metabolites are substances that are left behind when the body metabolizes a drug. For example, a cocaine user would have cocaine metabolites in his body, and some of these metabolites would make their way into his hair follicles. As such, it is possible to determine whether a person has recently used cocaine or another type of drug by performing a hair follicle drug test.

It's possible to determine whether a person has used cocaine by performing a hair follicle test.
It's possible to determine whether a person has used cocaine by performing a hair follicle test.

Hair follicle drug testing is often used as an alternative to testing urine. Often, it can provide a more accurate result simply because evidence of drug use may remain in a person’s hair follicles for longer than it does in urine. Typically, this type of testing can detect drugs that were used as long as 90 days before the testing took place. On the other hand, evidence of drug use may be detectable in urine for a much shorter period. A person may have a clean urine test in only a matter of days after using some drugs.

Hair follicle drug testing is capable of testing drug usage as far back as 90 days.
Hair follicle drug testing is capable of testing drug usage as far back as 90 days.

To perform a hair follicle drug test, the person performing the test has to obtain a hair sample. This type of drug testing typically requires a person to give a sample of about 50 to 70 hair strands. The amount of hair that is needed often depends on the color of the hair in question as well as its thickness. As far as length is concerned, the hair strands are typically about 1.5 inches (3.81 cm) long. The hair is usually cut as close to the scalp as possible, placed in a plastic bag, and sent to a lab for testing.

Some people may wonder whether it is possible to fool a hair follicle drug test. Some claim that using a particular shampoo will making beating a hair follicle test easy. In reality, however, it would be difficult for a shampoo to fool this type of test. Hair follicle drug screening is used to detect substances that have moved from the bloodstream into the hair strands. As such, washing the outside of the hair is unlikely to help. In some cases, people may decide to shave their heads in an effort to beat drug testing. This is also unlikely to produce the desired result, as body hair can be used if necessary.

When the body metabolizes a drug, some of the metabolites end up in the hair follicles.
When the body metabolizes a drug, some of the metabolites end up in the hair follicles.

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