Roche DAT immunoassay: sensitivity and specificity testing for amphetamines, cocaine, and opiates in oral fluid

Laboratory testing of oral fluid for drugs of abuse continues to expand in the workplace, legal, treatment, and health settings. In this study, we assessed recently developed homogeneous Roche DAT screening assays for amphetamines, cocaine metabolite [benzoylecgonine (BZE)], methamphetamines, and opiates in oral fluid. Precision and accuracy were assessed using control samples at +/-25% of cutoff. Sensitivity, specificity, and agreement compared to liquid chromatography-tandem mass spectrometry (LC-MS-MS) was assessed by analysis of oral fluid specimens collected from 994 subjects enrolled in a drug treatment or probation and parole drug-testing program. An additional 180 research specimens from Kroll Laboratories were analyzed for amphetamine and methamphetamine. Screening cutoff concentrations (ng/mL) were as follows: amphetamines, 40; cocaine metabolite, 3; methamphetamines, 40; and opiates, 10. LC-MS-MS analyses were performed with the following cutoff concentrations (ng/mL): amphetamine, 40; BZE, 2.0; methamphetamine, 40; and codeine or morphine, 10. The percent coefficient of variation ranged from 3.4% to 7.3%. Sensitivity and specificity of the Roche DAT assays compared to LC-MS-MS were > 94%, and agreement was > 96% for the four assays. The performance of the Roche DAT assays suggests these new homogeneous screening assays will be an attractive alternative to existing more labor-intensive enzyme immunoassays.