INTERFERENCE WITH TESTING FOR LYSERGIC-ACID DIETHYLAMIDE

We found a high rate (4.2%) of positive results for lysergic acid diet hylamide (LSD) by Emit in 1898 urine samples that were submitted prima rily from psychiatric patients for drugs-of-abuse (DOA) testing. Speci mens that tested positive for LSD by Emit subsequently tested negative for LSD with two RIAs. Furthermore, LSD was not detected in randomly selected Emit-positive urine samples by gas chromatography-mass spectr ometry. Normal urine samples tested positive for LSD by Emit when they were supplemented with therapeutic medications that were prescribed f or patients with positive urine LSD results by Emit. These therapeutic drugs interfered specifically with the Emit assay for LSD, since othe r Emit DOA tests were not affected by these medications at the tested concentrations.