Raising urinary citrate lowers calcium oxalate and calcium phosphate crystal formation in whole urine.

Crystal formation in whole urine was studied by the technique of rapid evaporation to 1,250 mosmol/l with and without raising citrate concentration by 40-50%. The added citrate reduced calcium oxalate crystal formation at pH 5.3 by about 25% and reduced calcium phosphate crystal formation at pH 6.8 by some 42%. These results support the view that citrate is important in maintaining calcium in solution in whole urine, and that raising the urinary citrate could be effective treatment for calcium oxalate/phosphate urolithiasis.