Buprenorphine (ng/ml) Norbuprenorphine (ng/ml) Patient CCF NMS Diff. (%) CCF NMS Diff. (%) 1 905 970 -6.9 827 970 -15.9 2 427 440 -3.0 469 440 6.4 3 261 220 17.0 233 220 5.7 4 173 180 -4.0 174 180 -3.4 5 96 82 15.7 89 82 8.2

Table 2: Method comparison using patient specimens spiked with unconjugated buprenorphine and norbuprenorphine. Five negative patient samples were spiked with different concentrations of buprenorphine and norbuprenorphine, and analyzed by the reported method (CCF) and an LC-MS/MS method offered at NMS Labs (Willow Grove, PA). The measured concentrations and the percent differences are shown.