[The significance of hypocitruria in calcium oxalate induced nephrolithiasis]

The citrate concentration of the daily collected urine was measured by citrate lyase method in 25 untreated patients with recurrent calcium stone disease (10 hypercalciuric and 15 normocalciuric) and in 11 patients with stone disease treated with hydrochlorothiazide and in 16 healthy controls. We found a great variancy of the results what rather looks like biological than methodic type. The concentration (1.99 +/- 1.33 mmol/l in normocalciuric and 2.77 +/- 1.62 in hypercalciuric stone formers but 5.06 +/- 2.81 in controls) and the daily output of the urinary citrate (2.74 +/- 1.38 mmol/d and 4.24 +/- 1.69 vs. 4.41 +/- 1.85) but not the citrate/creatinine ratio was significantly less in about the half of stone formers. The hypocitraturia was frequent in the normocalciuric and very rare in the hypercalciuric group of the renal stone patients. Measurement of the urine citrate concentration is more sensitive tool in the diagnosis of hypocitraturic state than daily citrate output while the latter is more characteristic for the patient, so common study of the two parameters is recommended.