70.69 x (cysC)-0.931
Abbreviations / Units
eGFR (estimated glomerular filtration rate) = mL/min/1.73 m2
cysC (cystatin C) = mg/L
- The cystatin-C based equation utilizes the Siemens (Date Behring) method and is not yet calibrated to IFCC standards. As a result, it may overestimate true GFR.
- To learn more, go to http://ckdepi.org/assays/cystatin-c/ or http://nkdep.nih.gov/lab-evaluation/cystatin-c.shtml.
- For use in children 1-18 years old.
- May be useful as a confirmatory test in specific circumstances when eGFR based on serum creatinine is less accurate, or when the clinical scenario warrants a secondary test.
- May serve as a reasonable alternative to the multivariate cystatin C equation when there is a concern about one of the major variables (height, Scr, or cystatin C.)
- In most cases, the Bedside Schwartz equation [0.413*(ht/cm/Scr)] allows rapid and reasonably accurate estimation of GFR for clinical use in children with CKD. When measurement and calibration is more broadly available, GFR estimates using cystatin C may also have broad clinical utility.
- Schwartz GJ, Schneider MF, Maier PS, et al. Improved equations estimating GFR in children with chronic kidney disease using an immunonephelometric determination of cystatin C. Kidney Int. 2012;82(4):445-453.
- Grubb A, Blirup-Jensen S, Lindstrom V, Schmidt C, Althaus H, Zegers I. First certified reference material for cystatin C in human serum ERM-DA471/IFCC. Clin Chem Lab Med. 2010;48(11):1619-1621.