Toxicological screening for drugs of abuse in samples adulterated with household chemicals.

Urine samples that tested positive for two drugs of abuse, namely cannabis and methaqualone, were reassayed in the presence or absence of common household chemicals: Jik (sodium hypochlorite), Dettol (chloroxylenol), G-cide Plus (glutaraldehyde), Perle Hand Soap, ethanol, isopropanol and peroxide (20 volumes). These chemicals are frequently used for the adulteration of urine samples. Department of Pharmacology, University of Stellenbosch. Household chemicals, at three different concentrations, were added to urine samples that tested positive for methaqualone and cannabis. Samples were reanalysed on an ETS Plus Analyser (Syva Company, San Jose, Ca.) using Emit drugs-of-abuse urine test reagents. Most of the chemicals tested influenced the outcome of positive toxicological screening results for these drugs. G-cide (glutaraldehyde) and Perle Hand Soap had the largest effect (false-negative) on the methaqualone test. Dettol (chloroxylenol) and Perle Hand Soap had the largest effect on the cannabis test. Higher concentrations of the adulterant were not always an indication of the extent of modification of the test result. The addition of certain chemicals (ethanol, isopropanol and peroxide) to the urine samples tested for methaqualone interfered with the test to such an extent that it gave invalid test results.