RESUMO
Serum and urinary uric acid, calcium and phosphorus besides urinary citric acid were estimated by colorimetric methods in 15 control subjects and 27 stone formers who were classified according to the type of their stones to the following groups [a] 15 cases with calcium oxalate stones, either pure or mixed with calcium phosphate and / or uric acid, [b] 6 cases with pure uric acid stone, and [c] 6 cases with magnesium ammonium phosphate stones either pure or mixed with ammonium urate. The data revealed that the urinary excretion of uric acid, calcium and phosphorus were within the normal range, while the urinary excretion of citric acid was significantly decreased in the three groups. This decrement could be due to impairment of kidney functions and /or bacterial infection. The serum levels were almost normal except few cases in the calcium oxalate group who showed hypocalcaemia