title: Radioimmunoassay of lysergic acid diethylamide (LSD) in serum and urine by using antisera of different specificities.
abstract: We raised high-titre antisera to two LSD-bovine serum albumin conjugates, one linked via the indole nitrogen, the other via the amide side-chain. The antisera were specific for different parts of the LSD molecule, as demonstrated by cross-reactivity studies with LSD, its metabolites, ergot alkoloids, and closely related compounds. The antisera were used to develop a double-antibody radioimmunoassay with a detection limit of about 0.4 mug of LSD per liter of unextracted urine or serum. We saw no nonspecific interference by urine, serum, or from a series of commonly used drugs. There was good correlation between immunoassay values obtained with the two antisera (r = 0.91). However, the antiserum linked via the indole nitrogen gave consistently higher results for samples from persons who had taken LSD, owing to greater cross-reactivity with LSD metabolites. Radioimmunoassay by use of two such antisera is a more specific screening procedure for LSD abuse than has been available previously. In addition, antisera cross-reacting with LSD metabolites allow measurement of these compounds, for which there is no satisfactory method at the concentrations found in biological fluids in man.
mesh_terms: D000918:Antibody Specificity; D006801:Humans; D007106:Immune Sera; D008238:Lysergic Acid Diethylamide / Q000032:analysis* / Q000097:blood / Q000652:urine; D011485:Protein Binding; D011863:Radioimmunoassay; D012710:Serum Albumin, Bovine
chemical_list: D007106:Immune Sera; D012710:Serum Albumin, Bovine; D008238:Lysergic Acid Diethylamide