title: Liquid chromatography-tandem mass spectrometry method for routine measurement of oxalic acid in human plasma.
abstract: A solid phase extraction (SPE)-LC-MSMS method for the routine determination of oxalic acid (OX) in plasma, a diagnostic marker of primary hyperoxaluria (PH), was developed and validated. The normal range of OX was found to be 3-11 micromol/L (n=67), with no differences attributable to gender or age. The effect of pre-analytical factors on the in vitro production of OX was investigated, and plasma was found to be stable for 1-2 h at room temperature, less after ingestion of vitamin C; the process was not completely stopped by preservation at either -20 or -70 degrees C.
authors.affiliation: Department of Medical Biochemistry, Rikshospitalet Medical Centre, Oslo, Norway. katja.elgstoen@rikshospitalet.no
authors.forename: Katja Benedikte Presto
authors.initials: KB
authors.lastname: Elgstoen