What Does Negative Drug Test Result Mean?
A negative drug test result generally means that testing did not detect the presence of a targeted drug (or its metabolites) in a particular sample.
However, in some cases a test result may be reported as negative even if trace amounts of the targeted drug are present in a test sample. Most laboratories apply federal drug testing guidelines when reporting drug test results. These guidelines require that a minimum amount of a drug be present before the test is reported as positive. Under these guidelines, a drug test that detects an amount of a substance that is less than the cut off concentration is reported as a negative drug test result. A negative drug test result may also be called a negative result.
WorkplaceTesting Explains Negative Drug Test Result
When drug testing is conducted in compliance with federal laws requiring such tests, the standards of the Substance Abuse and Mental Health Services Administration (SAMHSA) apply. Under these standards, a test must meet specific criteria to be deemed positive or negative. If neither of these categories is applicable, then a test result may be labeled inconclusive.
To qualify as a negative result, the test specimen must contain either none of the targeted drug (or its metabolites) or a concentration level that is less than the minimum threshold amount for that drug. Federal standards define this cut off concentration for each drug for which testing is required. Additionally, different cut off amounts are defined depending on the type of testing used.