The effect of pH on the risk of calcium oxalate crystallization in urine.
The risk of calcium oxalate (CaOx) crystallization at different pH levels was determined in urine from recurrent CaOx-stone formers and normal subjects. The highest crystallization risk was observed between pH 4.5 and 5.5. In the pH range 6.5-7.5, there was a marked increase in crystallization of calcium phosphate (CaP). The results suggest the beneficial effect of moderate alkalinization in terms of a reduced CaOx crystallization. Reduced CaOx crystallization occurs at the expense of an increased formation of CaP crystals. Whether this increases the risk of CaP-stone formation is not known, but the CaP crystals were usually small, at least below pH 7.5.
D002118:Calcium / Q000652:urine; D002129:Calcium Oxalate / Q000652:urine*; D002130:Calcium Phosphates / Q000652:urine; D003460:Crystallization; D006801:Humans; D006863:Hydrogen-Ion Concentration; D010070:Oxalates / Q000652:urine; D012306:Risk; D014545:Urinary Calculi / Q000209:etiology* / Q000652:urine
D002130:Calcium Phosphates; D010070:Oxalates; C485828:alpha-tricalcium phosphate; C485830:tetracalcium phosphate; D002129:Calcium Oxalate; C485838:calcium phosphate, monobasic, anhydrous; C020243:calcium phosphate; C485829:calcium phosphate, dibasic, anhydrous; D002118:Calcium