Hair tests are conducted to identify the long-term usage of weed in an individual rather than infrequent usage or just one time use. It takes about seven to ten days to detect the traces of marijuana constituents in your hair only after a week or more only depending upon the particular individual’s physiological conditions. Mass spectroscopy is the technique that is deployed to identify the traces of THC by products in your hair. This byproduct is called as THC-COOH.
Tests conducted on a person will show the results to be positive if and only if the traces of THC-COOH are more than fifty ng/ml in concentration. Therefore, naturally, when you are using marijuana infrequently, then you may not test positive for the test. In other words, you can escape the detector easily in spite of you using weed. Researches show that testing individuals that burn weed almost five days in a week, with the hair test, shown only 52% of the results to be positive. It means, weed do not stay in hair for long time and this cannot be used as a valid test to identify stoners, says, forensic science studies conducted by the university of Nebraska research team.
Again instead of smoking marijuana, if you choose to ingest it or eat it, then the traces of weed found on the hair is far lower compared to smoking weed. Better than the hair tests, urine tests give the ideal results for detecting marijuana smokers quite easily and quicker too. Urine tests are conducted to identify the metabolite THC-COOH present in the urine. Higher dosage of the contents of THC-COOH can show the results to be positive. Even days or weeks after the use of the drug one can possible detect the THC-COOH metabolites from urine easily. Even one time users are caught in this test.