BobToday
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Hair is a common method to test for drug use. Many companies/government organizations still use urine testing because it is less expensive, but hair testing is more accurate and can detect drug use for a longer period of time. When we ingest a drug or inhale the smoke of a drug, the substance enters our bloodstream. As soon as it enters, the liver begins to clean up the drug particles as contaminates. When the drug particles are cleaned up, waste from the particles goes back into the bloodstream where they are eliminated in one of several ways. Most of it is eliminated with urine. Before it is eliminated, however, some of it reaches our hair and nails. Our hair and nails are continuously being fed by our blood stream, and they are continuously growing. As the blood is used to make new hair, some of the drug and drug waste gets deposited in the hair. It takes about four days for the drug particles in the follicle to get into the base of the hair strand.
While urine testing usually cannot detect a drug more than a few days after use, hair testing has no limit. Testing companies usually impose their own limit of 90 days. Hair grows at a rate of about 1/2 inch per month. Testing companies take a small amount of hair, usually 40-50 strands. They begin testing from the top of the strand, which is the newest part of the hair, and they test downward to about 1 1/2 inches. This is what gives them the 90 day time span. If a person does not have hair on their head, body hair may also be used. Body hair grows at a different rate, and if body hair is tested, it may hold drug particles from the past year.
 Posted 5394 day ago
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