Background. This paper is about some compounds (calcium, oxalate, phosphate, uric acid, magnesium, citrate) of urinary, its excretion in 24 h urine of children with preurolithiasis. They play the most signifi cant role in the mechanism of the crystallization for the formation of kidney stones. Some aspects and risk factors of the format ion of kidney stones were discussed. There kidney stones form in response to genetic, environmental, metabolis risk factors.
Material and methods. Two groups of children were investigated: children with preurolithiasis (mean age 13 years) and 12 healthy children (the mean age 10 years) of control group. Children with connective tissue disease, different forms of glomerulonefritis or congenital nephropathy, urinary infection, gynecological diseases were excluded from the study.
Urine calcium, uric acid and phosphate were determined by classic spectrophoto- metrical methods, oxalate was measured by titration method, citrate and magnesium were detected by standardized reagents kits.
Results. The results from 24 h urine samples of vartous salts of the children with preurolithiasis compared to the healthy children showed that excretion of oxalate and uric acid was significantly increased (p<0.001), citrate decreased.
Citrate has a direct inhibitory effect on the crystallization and precipitation of calcium salts. Urinary citrate is considered an important inhibitor of the crys tal li zation of stone-form ing cal cium salts.
Conclusion. All investigation of urinary excretion salts as calcium, oxalate, phosphate, uric acid, magnesium, citrate are very important for diagnosis in children with preurolithiasis.
