Radioimmunoassay screening test for detection of phencyclidine (PCP, "angel dust") abuse among teenagers.

An immunogen was prepared from a succinamide derivative preparation of phencyclidine (PCP) and coupled to bovine gamma globulin by means of water-soluble carbodiimide. Phencyclidine, 10 of its analogs, and a 3,4-3H-PCP all bound competitively to antibodies induced in rabbits. An assay was developed using the ammonium sulfate precipitation separation method. The minimum detection limit to PCP was 2 ng/mL and that for various analogs ranged from 50 pg/mL to approximately 100 ng/mL. No cross reactivity was observed with at least 25 commonly used drugs. A double blind qualitative clinical evaluation of the assay was conducted with gas-liquid chromatography (GLC) and GLC-mass spectrometry methods. No false positive or false negative results were observed. For qualitative screening a "cut-off" level equivalent to 5 ng/mL was used for both serum and urine to distinguish between positive and negative specimens. Urine and serum samples from emergency room patients with neuropsychiatric symptoms and methadone clinic patients and autopsy material showed a significant incidence of PCP abuse, particularly among adolescents and young adults.