The excretion of pyrophosphate in daily, fasting and postprandial urine of patients with recurrent urolithiasis and in healthy controls

Abstract

Pyrophosphate (PPi) is excreted in human urine in amounts of up to 100 μmol/day (approx. 18 mg/day). It is considered an inhibitor of the nucleation, growth and aggregation of calcium-containing crystal phases in urine (1). If it played a role in the urinary inhibitor potential of recurrent calcium urolithiasis (RCU) patients, a clear-cut PPi deficit should be detectable in their undiluted urine. However, the literature referring to this issue gives contradictory data (2–4).