A Positive Drug Test in the Pain Management Patient: Deception or Herbal Cross-Reactivity?

Our laboratory was contacted by the Pain Management Center regarding a patient who tested positive for cocaine metabolite in urine, but denied abuse. Because this population is receiving prescriptions for controlled narcotics for pain, the physicians need to determine patient compliance and rule out abuse of street drugs for continued participation in the program. For this patient, the laboratory was consulted to distinguish whether the urine positivity was attributable to herbal medication cross-reactivity or whether the patient was deceiving the clinic physicians. The patient was a 47-year-old female with a history of Wegener granulomatosis and vasculitis. She had undergone extensive surgery, including resection of the frontal and nasal sinus cavity and septum, and was receiving aggressive analgesic management, including opioid analgesics for head pain related to her condition. It is the policy of the Pain Management Center to test all patients on a random basis three to four times a year for medication compliance and to exclude abuse of street drugs. The patient tested positive once before this episode for urine cocaine metabolite.