| Description |
The response to intensified urine testing for illicit drugs, drug users have attempted to falsify results by several schemes including in vitro adulteration of specimens. Additives that were claimed to invalidate enzyme immunoassay (EIA) drug assays were investigated. An investigation was also undertaken to determine whether adulterated urines could be identified so they might be rejected. Adulterants were added at several concentrations to 222 EIA positive specimens confirmed by gas chromatography and mass spectrometry (GC/MS) for illicit drugs. Specimens were reanalyzed by the EIA screening procedures using a Hitachi 704 analyzer. At the highest concentration evaluated, the adulterants (NaCl, Visine, Vestal medicated liquid handsoap, liquid Drano, liguid Chlorox bleach, Heinz vinegar, golden seal tea, and Real Lemon concentrated lemon juice) interfered with the drug assays differently. Barbiturate assays were affected by Visine, liquid handsoap, Drano and bleach. Cocaine assays were affected by NaCL, Drano and bleach. Opiate assays were affected by NaCl, Drano and bleach. The marijuana assays were affected by all except the lemon juice. The assays were unaffected by lower concentrations. To identify adulterated urines, we monitored pH, relative density, urine color and turbidity at adulterant levels which falsified the EIA results. Specimens contaminated with NaCL has specific gravities greater than 1.035. Liquid Drano, bleach and vinegar produced a urine pH outside of the physiological range. Golden seal tea caused a dark appearance, and specimens containing liquid soap were unusually cloudy. Lemon juice had no effect on the assays. Visine was the only adulterant not detected. Because EIA can be invalidated by specimen adulteration, drug testing should include assessment of pH, specific gravity and appearance. Suspect specimens should be rejected. Because not all adulterants can be detected, observed collection is recommended. |
