Contribution to therapeutic decisions of ratios, absolute values and other measures of calcium, magnesium, urate or oxalate balance in stone formers.

Investigation of multiple serum and urinary factors in 44 patients with calcium urinary stone disease confirmed a number of defects that have been described previously: elevation of mean serum calcium and uric acid above normal, and depression of mean serum magnesium. Urinary excretion of calcium and uric acid was increased and was increased and was probably related to food ingestion. Urinary magnesium also increased after eating but less than calcium, with the result that for most patients the magnesium to calcium x 100 ratio approached levels observed in stone formation. Urinary oxalate excretion was constant during the entire observation period and apparently was not affected by ingestion of a defined diet. Nine additional patients had persistent hypercalcemia owing to hyperparathyroidism (5 confirmed, 1 suspected), malignancy (2) and drug ingestion (1). Metabolic evaluation of patients with calcium urinary calculi continues to contribute to decisions regarding their best therapeutic regimen.