Oral fluid drug testing of chronic pain patients. II. Comparison of paired oral fluid and urine specimens.

A clinical study was conducted to compare the use of oral fluid to urine for compliance monitoring of pain patients. Patients (n = 133) undergoing treatment for chronic pain at four clinics participated in the study and provided paired oral fluid and urine specimens. Oral fluid specimens were collected with Quantisal(TM) saliva collection devices immediately following urine collection. Oral fluid specimens were analyzed for 42 drugs and/or metabolites by validated liquid chromatography-tandem mass spectrometry procedures. Accompanying urine specimens were initially screened by immunoassay and non-negative results were confirmed. Of the 1544 paired tests, 329 (21.3%) drug analytes were positive, and 984 (63.7%) were negative for both specimens resulting in an overall agreement of 85%. There were 83 (5.4%) analyte results that were positive in oral fluid and negative in urine, and 148 (9.6%) were negative in oral fluid and positive in urine for an overall disagreement of 15%. Cohen's Kappa value was 0.64, indicating "substantial" agreement. The primary exceptions to agreement were the lower detection rates for hydromorphone, oxymorphone, and benzodiazepines in oral fluid compared to urine. The authors conclude that, overall, oral fluid tests produced comparable results to urine tests with some minor differences in detection rates for different drug classes.

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 non-negative 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.