title: False-positive buprenorphine EIA urine toxicology results due to high dose morphine: a case report.
abstract: In monitoring a patient with chronic pain who was taking high-dose morphine and oxycodone with weekly urine enzymatic immunoassay (EIA) toxicology testing, the authors noted consistent positives for buprenorphine. The patient was not taking buprenorphine, and gas chromatography/mass spectroscopy (GCMS) testing on multiple samples revealed no buprenorphine, indicating a case of false-positive buprenorphine EIAs in a high-dose opiate case. The authors discontinued oxycodone for a period of time and then discontinued morphine. Urine monitoring with EIAs and GCMS revealed false-positive buprenorphine EIAs, which remained only when the patient was taking morphine. When taking only oxycodone and no morphine, urine samples became buprenorphine negative. When morphine was reintroduced, false-positive buprenorphine results resumed. Medical practitioners should be aware that high-dose morphine (with morphine urine levels turning positive within the 15,000 to 28,000 mg/mL range) may produce false-positive buprenorphine EIAs with standard urine EIA toxicology testing.
authors.affiliation: Albert Einstein College of Medicine, Bronx, New York 10461, USA. ptenore@dosa.aecom.yu.edu
authors.forename: Peter L
authors.initials: PL
authors.lastname: Tenore
mesh_terms: D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000652:urine*; D002047:Buprenorphine / Q000652:urine*; D002908:Chronic Disease; D057075:Enzyme Assays / Q000379:methods; D005189:False Positive Reactions; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D017116:Low Back Pain / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D009020:Morphine / Q000008:administration & dosage* / Q000652:urine; D010098:Oxycodone / Q000008:administration & dosage / Q000652:urine; D011933:Reagent Kits, Diagnostic
chemical_list: D000701:Analgesics, Opioid; D011933:Reagent Kits, Diagnostic; D002047:Buprenorphine; D009020:Morphine; D010098:Oxycodone