The oxalate-tolerance-value: a whole urine method to discriminate between calcium oxalate-stoneformers and others

In undiluted urine portions the oxalate-concentration required for precipitation (= oxalate-tolerance) can be obtained by titration with sodium-oxalate and turbidimetric detection. The corresponding urinary calcium-concentration was measured and the two values plotted against each other. With regard to a standard-curve (measurements in synthetic urine) different behaviour between urines of stone forming patients and others can be observed.