What is a Drug Test Cutoff Level?

Substance abuse among individuals rises problems at home, school, organizations and also society. Hence, there is a need to conduct drug testing at these locations to identify drug abusers and control their unhealthy habit. Drug testing kits that enable detection of various drugs are designed with specific cutoff levels to provide accurate results. A drug test cutoff level is the minimum concentration of drug at or above which the result of a drug test is considered positive. Drug test cutoff levels have lot of significance in drug tests.

If the concentration of drugs is found to be at or above the cutoff level, the result is considered as positive. If the concentration of drugs or their metabolites are lower than the cutoff level, then the result is considered negative. Standard cutoff levels should be set for drug test in order to ensure the accurate results.

The cutoff levels for initial drug tests vary for different drugs – 50ng/ml (nanograms per milliliter) for marijuana, 150 ng/ml for cocaine, 2000 ng/ml for opiates, 25 ng/ml for phencyclidine (PCP), 500ng/ml for amphetamine. Once the initial tests are done, confirmatory tests are even conducted to ensure the results are right. The confirmatory drug cut off levels of various drugs are : 15ng/ml for marijuana, 100ng/ml for cocaine, 2000ng/ml for opiates, 25 ng/ml for PCP, and 250ng/ml for amphetamine. With improper standard set of cutoff levels, there are chances of false positive or false negative results. Hence, ensure that you choose the drug test kits designed with standard cutoff levels.