Specimen Adulteration in Drug Urinalysis

Data from samples adulterated with a variety of substances have been described with respect to their effects on a number of testing methodologies. Several substances have been shown to produce false negative results while others cause positive results in the screening test. Some adulterants cause samples to be negative because the drug, or metabolites, of interest is changed or destroyed while others effect the assay itself. No evidence exists to suggest that an adulterant can cause a false positive result if good forensic procedures are followed including confirmation of initial positive results using a second methodology based on a different chemical principle such as gas chromatography/mass spectrometry.