Definition - What does Non-Negative Specimen mean?
In general, a non-negative specimen refers to any specimen which, upon testing for the presence of a targeted substance, produces any non-negative result.
Specifically, federal drug testing rules for urine drug testing categorize a result as non-negative if the test result for the specimen is positive, adulterated, substituted, or invalid. For example, a specimen may be categorized as non-negative if it validity testing indicates that the specimen has been diluted or adulterated. In these instances, tampering may prevent the specimen from testing positive for the targeted drug but cannot rule out the possibility of drug use by the test subject.
WorkplaceTesting explains Non-Negative Specimen
A non-negative specimen is not the same as a positive specimen. A drug test result is categorized as positive if testing indicates the presence of a targeted drug or its metabolite at a level above the minimum threshold or cut off. However, a non-negative specimen also does not clearly indicate that the test subject has not used prohibited drugs.
When a urine specimen is initially collected, an instant or point of collection test may be performed. This instant may result in either an unequivocal negative finding or a non-negative finding that necessitates further investigation. Employers who are not required to conduct lab tests pursuant to the Federal Department Of Transportation (DOT) guidelines may elect to only pursue lab testing for non-negative specimens as a cost saving measure by using point of collection testing to identify negative specimens that do not require further analysis.
Under federal rules for drug testing, a specimen that has been tested and deemed non-negative may eligible for a split specimen test. An individual whose specimen is non-negative may also be permitted to provide evidence to a medical review officer indicating the reasons for the non-negative result.