This discussion has no relevance in pediatrics, given that children with reduced GFR already have clear evidence of renal injury. In children, clearance discrepancies are visible only in those with high body weight.
If cystatin C is measured, it is suggested that the healthcare professional should:
Use eGFRcys more than the isolated cystatin concentration;
Understand situations where eGFRcys and eGFRcreat-cys are less reliable.
Clinical laboratories that measure cystatin should (1B):
Dose it using a test with calibration referenced to international standards;
Report the eGFRcys result with serum cystatin in adults and specify the equation used whenever using eGFRcys and eGFRcreat-cys;
Report eGFRcys and eGFRcreat-cys in adults, using the 2012 CKD-EPI formula for cystatin C or alternative formula for cystatin C if it shows better accuracy when compared to that of 2012.
When reporting serum cystatin C results:
Provide cystatin C concentration results rounded to the nearest hundredth of an integer, expressed in conventional units (mg/l).