Hair drug tests are one of the best methods for detecting long term drug use. The drugs that you consume are widely distributed in the body and they make way to the hair follicles and get lodged there for some months. Depending upon the usage of the drug (recreational, short term and long term), the concentration of the drug varies in the hair follicles. Every drug has minimum cut off concentration below which it can not be detected in hair follicle. Some of the commonly tested drugs using the hair samples are amphetamines, cocaine, opiates, PCP and THC.
The hair drug test kit comes with the instruction manual, the self addressed envelope, and other things. All you have to do is to get a hair sample 1.5 inches in length and must be cut as close to the scalp as possible. Every 0.5 inches of the hair sample resembles 1 month. Once you cut a scalp of hair with the thickness of about a shoe lace, then you have to send it to the testing laboratories using the self addressed envelope.
One of the advantages of hair drug testing is that the drug can be detected from the hair from any part of the body. But the rates of growth of hair differ from one another. It usually takes 4 to 5 days for the drug to be detected in the hair follicle after the consumption of the drug. The idea behind this is that the hair must grow above the level of the scalp so that it can be detected. The ability of the hair drug test to detect drug from the hair from any part of the body has made it very popular. Even if the hair is shaven off completely, the hair follicles would still retain them as long as they are replaced.
The hair follicle drug test is done using gas chromatography and mass spectrometry tests. The testing is not restricted to the parent drug rather it is extended even for the metabolites which rules out the possibility of exogenous contamination of drugs.
Before you perform the test, you must gain adequate hair follicle drug test information. Using shampoos, detoxifiers, bleachers, etc would seldom alter the quantitative results of the drug testing. Never mix the hair samples obtained from two different parts of the body. And also never collect the hair samples from the hair brush.