title: Interference with testing for lysergic acid diethylamide.
abstract: We found a high rate (4.2%) of positive results for lysergic acid diethylamide (LSD) by Emit in 1898 urine samples that were submitted primarily from psychiatric patients for drugs-of-abuse (DOA) testing. Specimens 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 spectrometry. Normal urine samples tested positive for LSD by Emit when they were supplemented with therapeutic medications that were prescribed for patients with positive urine LSD results by Emit. These therapeutic drugs interfered specifically with the Emit assay for LSD, since other Emit DOA tests were not affected by these medications at the tested concentrations.
authors.affiliation: Pathology and Laboratory Medicine, John Cochran Veterans Affairs Medical Center, Saint Louis, MO 63106, USA. ritterdg@sluvca.slu.edu
authors.forename: D
authors.initials: D
authors.lastname: Ritter
authors.forename: C M
authors.initials: CM
authors.lastname: Cortese
authors.forename: L C
authors.initials: LC
authors.lastname: Edwards
authors.forename: J L
authors.initials: JL
authors.lastname: Barr
authors.forename: H D
authors.initials: HD
authors.lastname: Chung
authors.forename: C
authors.initials: C
authors.lastname: Long
mesh_terms: D017248:Enzyme Multiplied Immunoassay Technique / Q000706:statistics & numerical data; D005189:False Positive Reactions; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D008238:Lysergic Acid Diethylamide / Q000652:urine*; D011786:Quality Control; D011863:Radioimmunoassay; D015813:Substance Abuse Detection
chemical_list: D008238:Lysergic Acid Diethylamide