Hypocitraturia

Overview
Hypocitraturia, a low amount of citrate in the urine, is an important risk factor for kidney stone formation. Citrate in the urine has long been recognized as an inhibitor of calcium salt crystallization.

Citrate is the dissociated anion of citric acid, a weak acid that is both ingested in the diet and produced endogenously in the tricarboxylic acid cycle.

The mean urinary citrate excretion is 640 mg/d in healthy individuals.

Hypocitraturia usually is defined as citrate excretion of less than 320 mg/day, but this definition has been challenged as inadequate for recurrent stone formers.


 * Severe hypocitraturia: citrate excretion of < 100 mg/day
 * Mild-to-moderate hypocitraturia: citrate excretion of 100-320 mg/day

Other definitions;


 * Urine citrate level < 220 mg/day for both men and women, regardless of age, or


 * Urine citrate level < 115 mg/day in men and < 200 mg/day in women.