Hair is one of the best specimens in certain cases of hair follicle drug test. Though hair drug test is quite expensive it is the only sample by which drugs can detected even after 90 days of drug addiction. Drugs when are exposed to the human body will get metabolized in to their active metabolites. Metabolites will get dissolved in blood or excreted in the urine. Some of the drug metabolites will get deposited in the fatty substance, in the hair shafts. Drugs which are accumulated in the hair shafts will persist for long time and mixed with it. Drug metabolite becomes one of the nutrients for the hair growth and grows along the hair. Hence it is quite tough to remove the drug metabolite from the hair specimen. Even if you shave or shampoo your hair it does not work. For this reason hair drug test is considered as the effective method compared to other methods of drug testing.

Hair follicle drug testing involves very simple procedure and has become a small business. Hair drug testing can be performed by the professional doctors and skilled labors at lab. Those who are indulged in drug testing work should have lab and instrument technique skill and should know about the drug and its function thoroughly. This will aid them to produce effective and better results. If they do not handle the instrument or sample properly negative result may be reported. Utmost care and sincerity is required to work in drug testing laboratory to produce good report.

Home drug test hair is also available in the form of hair drug test kit which can be purchased from the medical shops. Drug testing hair sample provides the enough information about the drug addiction in a person. Thus hair sample is considered to be more valuable sample.