Question
What are adulterants? Can labs screen them?
Answer
Adulterants are substances added to a specimen to produce a false negative that donors can consume through over-the-counter products. An adulterated specimen may contain a substance that is not normally found in human urine. Labs do screen for adulterants, but may encounter difficulty with identifying the drugs the donor was trying to conceal.
Also see Help me understand MRO reviewed results of a drug screening.