Enzymatic Determination of Oxalate in Urine
Oxalate is a major component of urinary stones and its concentration in urine is important for urolithiasis. Many methods have been described for the determination of oxalate in urine, but so far none has found application in the routine clinical laboratory. The classical chronotropic acid procedure1 is time-consuming, non-specific, and susceptible to interference. Techniques such as gas-chromatography, HPLC and ion-chromatography involve complex methodology and specialized equipment. We have developed a simple and specific spectrophotometric assay, based on the method of Beutler et al2, using the enzymes oxalate decarboxylase and formate dehydrogenase. In addition, a method of sample preparation is described which prevents the precipitation of oxalate during storage, resulting in better recovery and precision.
KeywordsOxalic Acid Nicotinamide Adenine Dinucleotide Urinary Stone Nicotinamide Adenine Dinucleotide Formate Dehydrogenase
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