title: Spurious hyperbilirubinemia caused by naproxen.
abstract: OBJECTIVE
  To confirm that the naproxen metabolite O-desmethylnaproxen interferes with the Jendrassik and Grof method for total bilirubin and was a possible cause of spurious hyperbilirubinemia in a case of naproxen overdose.
  
  
  METHODS
  Plasma was spiked with naproxen or O-desmethylnaproxen before total and direct bilirubin analysis.
  
  
  RESULTS
  O-desmethylnaproxen concentration showed a linear relationship with measured total bilirubin.
  
  
  CONCLUSIONS
  O-demethylnaproxen interferes with the total bilirubin method. Interference of glucuronide metabolites of naproxen and O-demethylnaproxen is not excluded.
authors.affiliation: University of British Columbia Department of Pathology and Laboratory Medicine, Vancouver, BC, Canada.
authors.forename: Nafila
authors.initials: N
authors.lastname: Al Riyami
authors.forename: Amanda C
authors.initials: AC
authors.lastname: Zimmerman
authors.forename: Frances M
authors.initials: FM
authors.lastname: Rosenberg
authors.forename: Daniel T
authors.initials: DT
authors.lastname: Holmes
mesh_terms: D000328:Adult; D001663:Bilirubin / Q000032:analysis; D006801:Humans; D006932:Hyperbilirubinemia / Q000139:chemically induced*; D008297:Male; D009288:Naproxen / Q000009:adverse effects*
chemical_list: D009288:Naproxen; D001663:Bilirubin