CystatinC in the measurement of eGFR

Last edited 09/2021

The Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) have developed equations to calculate eGFR based on serum creatinine; and another equation based on serum creatinine plus serum cystatin C

  • in patients with near-normal kidney function, the Modification of Diet in Renal Disease (MDRD) equations underestimate GFR
    • the CKD-EPI2009Scr equation partly overcomes the major limitation of the MDRD equation
  • the CKD-EPI working group has two newer CKD-EPI equations:
    • one using cystatin C concentration (CKD-EPI2012cys) and the other using both cystatin C and serum creatinine concentrations (CKD-EPI2012Scr-cys)
    • they validate the new equations represent an advance over currently available equations across the range of GFR and in relevant subgroups
      • the advance even holds true among participants with an extreme body-mass index of less than twenty. The two new equations even have been recommended by KDIGO 2012Clinical Practice Guidelines for the Evaluation and Management of CKD (2)
      • there has been data that the CKD-EPI2012Scr-cys is superior to calculations based on serum creatinine alone (3,4,5)
        • a study in Chines population ((n = 788; median age, 54 [range, 19-94] years)) concluded (5) '..CKD-EPI2012Scr-cys appeared less biased and more accurate in overall participants. Neither of the new CKD-EPI equations achieved ideal accuracy in senior participants with moderately-severely injured GFR...'
      • a review states that overall, the CKD-EPICR-CYS equation had better precision and accuracy than that based on creatinine alone or CysC alone (6)