A new homogenous microparticle-based immunoassay (Abuscreen OnLine) detects LSD in human urine at a cutoff of 0.5 ng/mL, matching the sensitivity of the existing Abuscreen RIA. All 31 samples previously confirmed positive by gas chromatography-mass spectrometry also tested positive with both the OnLine and RIA assays. Among 1,000 presumed negative samples, 992 (99.2%) were negative; the 8 OnLine positives were negative by RIA. The assay shows greater than 35% cross-reactivity to nor-LSD and similar cross-reactivity to other related compounds as the RIA. Within-run precision was less than 2.5% and between-run precision less than 3.0%.
Three lysergic acid diethylamide (LSD) derivatives were synthesized and characterized. The most stable derivative was selected and covalently linked to polystyrene microparticles through a carrier protein. Two new LSD immunogens were synthesized, generating antibodies that recognize LSD and several major LSD metabolites. A homogeneous microparticle-based immunoassay was developed for detecting LSD in human urine with sufficient sensitivity and specificity for effective screening. The assay's performance was evaluated using precision, cross-reactivity, correlation to the Abuscreen LSD RIA and GC/MS/MS, specificity, and limit of detection.