Evaluation of Buprenorphine LUCIO Immunoassay versus GC–MS Using Urines from a Workplace Drug Testing Program

was evaluated. Urine samples from subjects enrolled in a work-place drug testing program were screened according to the manu-facturer’s instruction using a Roche COBAS Integra 800 analyser. For gas chromatography–mass spectrometry (GC–MS) confirma-tory analysis, samples were submitted to enzymatic hydrolysis with b-glucuronidase and mixed-mode solid-phase extraction. Imprecision (coefficient of variation) for 3.0, 7.0, and 13.0 ng/mL calibrators varied within 2.8–8.7 intra-day (n5 20) and 7.7–8.6 inter-day (n5 19). Inaccuracy (bias) was between –5.6–30.5 intra-day and –13.2–4.2 inter-day. At the 5 ng/mL cut-off, the im-munoassay showed 100 % sensitivity and 88 % specificity, with an overall agreement of 94 % between immunoassay and GC–MS. Raising the cut-off to 10 ng/mL provided an identical overall agreement between immunoassay and GC–MS (94%), despite the decrease in sensitivity (90%) and the increase in specificity (100%). According to these results, the BUP LUCIO Nal Von Minden screening assay provides adequate sensitivity and specifi-city for BUP screening in urine samples using a cut-off concentra-tion of 5 ng/mL