[Laboratory methods of predicting primary and recurrent nephrolithiasis].

Concentrations of Na, K, Ca ions, oxalic and uric acids, total Ca, P as well as urease activity, the ability to form crystals, speed of crystallization, crystal chemical composition, pH stability were evaluated in the urine from 40 urolithiasis patients and 40 patients with recurrent nephroliths. It was found that fast or moderate crystallization, high urease activity and ability to form crystals, unstable urine pH indicate a high risk of both primary and recurrent nephrolith formation.

[Urinary urease activity in urolithiasis patients].

Urease activity (UA) and the ability of the urine to form crystals (AFC) were assessed in the urine from 149 urolithiasis patients and 11 healthy controls. Patients with primary uroliths had high UA and AFC in 17-18% of the cases, in recurrent urolithiasis this percentage was 29-35%. The speed of phosphate and oxalate crystals formation as well as formation of renal calculus correlated with UA and UA levels.