Quantitation of glycolate in urine by ion-chromatography

Most kidney stones are composed principally of calcium oxalate. The major precursor of oxalate in man in glyoxylic acid. Glycolic acid plays an intermediate role in glyoxylate metabolism being involved in both its synthesis and degradation [1]. The identification and differentiation of specific types of kidney stone disease is partially based on the measurement of glycolic acid [2]. However, a large variation (1 to 100 mg/24 hr) in urinary glycolate values has been reported in the literature [3, 4]. Due to this variability the role of glycolic acid in the diagnosis of nephrolithiasis is still mostly undetermined.