Validation of the Cozart Amphetamine Microplate EIA for the analysis of amphetamines in oral fluid

The purpose of this study was to determine the performance characteristics of the Cozart Amphetamine Microplate EIA for detecting amphetamine in oral fluid. Oral fluid samples were collected using the Cozart RapiScan Collection System from 135 volunteer donors from drug treatment clinics. A further 35 oral fluid samples were collected from volunteer donors who were not drug users. The samples were analyzed in the laboratory using the Cozart Amphetamine Microplate EIA and confirmed using gas chromatography-mass spectrometry (GC-MS). The samples were stored frozen until analysis by GC-MS. The intra-assay precision for the Cozart Amphetamine Microplate EIA for amphetamine in oral fluid over forty assays was 2.74-7.1% CV (within assay) and 3.4-7.0% CV (within day). A total of 78 samples were positive for various amphetamines and related designer drugs. The Cozart Amphetamine Microplate EIA, using a cutoff of 45 ng/ml amphetamine equivalents in neat oral fluid, had a sensitivity of 91.7+/-3.3% and a specificity of 95.9+/-1.9% versus GC-MS using a cutoff of 30 ng/ml. A series of potential adulterants of oral fluid were evaluated and shown not to alter the outcome of the test result.