Determining the effects of adulterants on drug detection via enzyme-linked immunosorbent assay and adulterant tests strips.

The use of immunoassays for drug screening has increased due to their sensitivity towards target analytes, specifically the enzyme-linked immunosorbent assay (ELISA) technique. Adulterant test strips are commonly used in conjunction with immunoassay tests to ensure the integrity of the specimen has not been altered prior to drug screening. This research focuses on determining which adulterants can produce a false negative result, not only with 1 of the screening tests, but throughout the entire screening process. Seven adulterants were tested for their ability to generate false negative results for the ELISA by decreasing the detectable antigen concentration to below industry-used cut-off levels. Each adulterant was added to a urine sample containing 1 of 5 different drugs at 5 different concentrations (0, 5, 10, 25, and 50%). Five different urine samples that contained drugs and drug metabolites of benzoylecgonine, THC-COOH, α-PVP, D-amphetamine, and Diazepam, were treated with each of the 7 adulterants and analyzed on the ELISA and subsequently by 2 different test strips. The results indicated that 4 adulterants (ie, bleach, Drano®, vinegar, and sodium nitrite) generated the most false negatives for both test strips and the ELISA at surprisingly low concentrations, ~5% v/v. Thus indicating that there are still ways that a urine sample that contains drugs could be analyzed and labeled "clean and free of drugs" after going through a common screening process. These results suggest that new drug screening techniques need to be developed to detect adulterants in urine samples for drug screening.