Calculated result using the CKD-EPI formula
A variety of methods have been used. All are based on serum creatinine estimations.
Although the Cockcroft-Gault formula is widely used, it was developed to permit estimation of CrCl, not of GFR.
The best validated method comes from the MDRD Study data (Ann Int Med 130:461-70, 877-84, 1999). The study derived a number of equations. The abbreviated, or four-variable equation includes age, sex, creatinine, and race (black or not black). Adding more variables (albumin, urea) adds little to accuracy.
It is important to be aware of the limitations of these equations (more info on eGFR from the UK CKD eGuide):
Most UK labs now report eGFR when returning creatinine values. When available, these values should be more accurate than calculations performed by you, as they should incorporate lab-specific correction factors. If not, here are some resources:
The UK Renal Association Website – www.renal.org/eGFR
Online calculator from nephron.com offers a simple abbreviated MDRD, and has a useful menu of alternatives including quaint US units and also Cockroft-Gault. Take care to set units for [creat] correctly.
Only calculated for patient’s greater than 18 years with values less than 60 reported
Estimation of glomerular filtration rate
LocalSpecimen Labelling Procedure