High prevalence of urine tampering in an office-based opioid treatment practice detected by evaluating the norbuprenorphine to buprenorphine ratio

Testing for buprenorphine metabolites yields valuable clinical information. The prevalence of a result pattern consistent with tampering by “urine spiking,” the addition of unconsumed buprenorphine into the urine sample, may be higher than previous estimates. Previous lower cutoffs of the norbuprenorphine:buprenorphine metabolic ratio may miss a substantial proportion of these likely tampered samples.