Ion-chromatographic measurement of oxalate in unprocessed urine.

We describe a sensitive, simple technique for determining urinary oxalate. Urine, diluted as necessary with distilled water, is injected into an ion chromatograph. Oxalate is detected conductimetrically as a distinct peak near the tail of the chromatogram. This peak specifically represents oxalate, because it is abolished if the sample is treated with oxalate decarboxylase. We have used this technique to measure oxalate in more than 3000 consecutively received urine samples. It has a CV of 6%.