Drug testing is done for many reasons including for candidates looking to get hired for work. Urine testing and blood testing are the commonly used methods for drug testing. In the case of urine testing, there may be more risks associated with false results such as when an individual uses substances to cover up the presence of drugs. Hair follicle testing can also be more accurate in detecting certain classes of drugs than urine testing and for a longer period of time.


Whether drugs have been smoked, snorted, injected by needle, or ingested, the drugs enter the bloodstream and travel through the body. Hair testing is done to identify specific drugs. Follicles in the hair are used in the testing where the molecules of the drugs are noted after they have been processed in the body. The bloodstream carries trace amounts of the molecules into the follicle of the hair. Hair testing allows drugs in the body to be identified after being ingested for up to a 9 day period. This means that any drug use over the course of three months will likely show up in test results. Longer hair strands may allow for testing results to exceed the standard 90 day time period.


Hair will need to be cut very close to the scalp. Usually a half to a whole inch is necessary for testing. Follicle testing can identify many types of drugs including marijuana, cocaine, opiates, phencyclidine, and methamphetamines all of which encompass the five main categories of drugs as per the federal laws.


Typically follicle testing involves hair follicles found on an person’s head. However, when a subject is bald or shaves their head, body hair from other areas can be utilized for accurate testing. Because body hair grows at a much slower rate than hair on the head, testing can produce results containing drugs used for up to a year after use.