Spurious hyperbilirubinemia caused by naproxen.
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.
Al Riyami
Nafila
N
University of British Columbia Department of Pathology and Laboratory Medicine, Vancouver, BC, Canada.
Zimmerman
Amanda C
AC
Rosenberg
Frances M
FM
Holmes
Daniel T
DT
D000328:Adult; D001663:Bilirubin / Q000032:analysis; D006801:Humans; D006932:Hyperbilirubinemia / Q000139:chemically induced*; D008297:Male; D009288:Naproxen / Q000009:adverse effects*
D009288:Naproxen; D001663:Bilirubin