The determination of oxalate in the urine by a new enzymatic method using oxalate oxidase

: Oxalate is one of the most important constituents in urine of urinary stone. But the determination of oxalate in urine has not been performed as a routine laboratory examination because of difficulty or inaccuracy in measuring oxalate in urine. We tried to measure oxalate in urine by the newly developed enzymic method with oxalate oxidase. This method is not only simple but also accurate enough. The reproducibility S.D./mean was 2.3-9.0%, the recovery rate was 95.2 +/- 4.0% (mean +/- S.D.) With this method, the normal range of urine oxalate in 24 hours was determined to be 11.8 mg-39.4 mg, the upper limit was 40 mg. By taking the regular diet which contains 500 mg of calcium and 1,000 mg of phosphorus a day, the excretion of oxalate in urine was significantly decreased in the stone formers. This suggests that the influence of the diet upon the excretion of oxalate in urine for 24 hours is important especially in stone formers.