Oral fluid drug testing of chronic pain patients. I. Positive prevalence rates of licit and illicit drugs

Oral fluid compliance monitoring of chronic pain patients is an analytical challenge because of the limited specimen volume and the number of drugs that require detection. This study evaluated oral fluid for monitoring pain patients and compared results to urine studies of similar populations. Oral fluid specimens were analyzed from 6441 pain patients from 231 pain clinics in 20 states. Specimens were screened with 14 ELISA assays and nonnegative specimens were confirmed by LC-MS-MS for 40 licit and illicit drugs and metabolites. There was an 83.9% positive screening rate (n = 5401) of which 98.7% (n = 5329) were confirmed at ≥ LOQ concentrations for at least one analyte. The prevalence of confirmed positive drug groups was as follows: opiates > oxycodone > benzodiazepines > methadone ≈ carisoprodol > fentanyl > cannabinoids ≈ tramadol > cocaine > amphetamines ≈ propoxyphene ≈ buprenorphine > barbiturates > methamphetamine. Approximately 11.5% of the study population of pain patients apparently used one or more illicit drugs (cannabis, cocaine, methamphetamine and/or MDMA). Overall, the pattern of licit and illicit drugs and metabolites observed in oral fluid paralleled results reported earlier for urine, indicating that oral fluid is a viable option for use in compliance monitoring programs of chronic pain patients.