Abstract
Different mathematical expressions of urinary calcium, oxalate, magnesium, citrate and urine volume(V), formulated in order to reflect supersaturation with respect to calcium oxalate, were compared with the computercalculated ion-activity product of calcium oxalate (AP(CaOx))- A good correlation (r = 0.99) was demonstrated for the following two simplified relationships and AP(CaOx): Ca^0.71 X Ox and (Ca^0.71 X Ox)/V^1.2. The correspondence between Ca/Mg quotients and AP(CaOx) was generally less satisfactory.