cystatin C, cystatin C/crea, urinary cystatin C in healthy children

The level of urinary cystatin C in urine in healthy adult individuals is 0.095 mg/l (0.033 - 0.29 mg/l) and it increases when increasing the age. Cystatin C is freely filtered in glomeruli and re-absorbed by the proximal tubular cells where it is also completely degraded. Increased urinary concentration of cystatin C is a marker of the functionality of cells. Disrupted glomerular filtration can be detected on the basis of increased levels of cystatin C in plasma. Plasma level of cystatin C increases with the age as a result of filtration rate decline. Aims of the study are to asses ?normal? cystatin C values in the urine of healthy children and to evaluate the obtained reference ranges after correction to urinary creatinine.