Influence of gender and age on calcium oxalate crystal growth inhibition by urine from relatives of stone forming patients.

Purpose: We define the relationships between urine inhibition of calcium oxalate crystal growth and age, gender, urine chemistries and stone formation among relatives of calcium stone forming patients.

Materials And Methods: We collected 24-hour urine samples from 366 first degree relatives of calcium stone formers. Calcium oxalate crystal growth inhibition was studied using a constant amount of dialyzed urine protein in a seeded crystallization system.

Urinary stone risk factors in the siblings of patients with calcium renal stones.

Purpose: We determined which, if any, urinary stone risk factors accurately discriminate stone forming and nonstone forming siblings of patients with calcium renal stones.

Materials And Methods: A total of 252 siblings of stone formers provided 2, 24-hour urine samples, which were sent overnight and analyzed at a central laboratory. Standard stone risk factors were measured and the supersaturation of calcium oxalate, calcium phosphate and uric acid was calculated.