Abstract: The invention is a method to detect adulterated specimens submitted for substance abuse. It is concerned with testing a sample of the submitted urine, and in a parallel test analyze a sample of the submitted urine to which has been added known amount of the suspected substance. A control artificial urine with the same concentration of suspected substances as the added known amounts is analyzed in a third parallel test. If the measured amounts of the suspect drug is less than the additive amounts of the submitted urine plus the added know substances the specimen sample is suspect and subject to further consideration.