Raising Urinary Citrate Lowers Calcium Oxalate and Calcium Phosphate Crystal Formation in Whole Urine

Abstract

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.