Oxalate status in stone-formers. Two distinct hyperoxaluric entities.

A retrospective analysis of oxalate status in 115 stone-forming individuals revealed hyperoxaluria in 30%. These individuals could be divided into two distinct groups according to urinary oxalate excretion patterns and plasma oxalate levels. The cause of hyperoxaluria in one group may be explained on the basis of increased absorption of dietary oxalate and decreased renal clearance. Hyperoxaluria in the other group appears to be a consequence solely of enhanced endogenous production of oxalate. These two entities can be distinguished from one another in the context of a routine metabolic evaluation of calcium stone disease when urine and plasma oxalate measurements are included.