Validation of the Cozart® microplate EIA for analysis of opiates in oral fluid

The purpose of this study was to determine the performance characteristics of the Cozart® microplate EIA for detecting opiates in oral fluid from patients in a drug misuse treatment program. Oral fluid samples were collected using the Cozart® RapiScan Collection System from 216 donors who were receiving treatment for their addiction and were monitored for drug abuse. A further 40 oral fluid samples were collected from volunteer donors who were not drug users. The samples were analyzed in the laboratory by using the Cozart® microplate EIA for opiates 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® microplate oral fluid EIA for opiates over 40 assays was 0.43% to 9.13% CV (within assay) and 2.9% to 9.1% CV (within day). A total of 109 samples were positive for various opiates. The Cozart® microplate EIA for opiates in oral fluid, using a cut-off of 30 ng/ml morphine equivalents in neat oral fluid, had a sensitivity of 99.1 ± 2.1% and a specificity of 94.4 ± 2.2% versus GC-MS. A series of potential adulterants of oral fluid were evaluated and shown not to alter the outcome of the test result.