Estimated GFR [eGFR]

eGFR is a test of kidney function. It uses the result of your Creatinine test with your age and sex to estimate an approximate percentage kidney function. eGFR is only an approximate number, but gives a better idea of kidney function than Creatinine alone. If you are of black African origin, you should add 20% to the figure (this correction is unlikely to have been made in the lab). Normal is over 90 ml/min/1.73m2. 'Normal' eGFR is the same for all ages and for men and women. Calculating eGFR doesn't make sense in patients on dialysis. If you are on dialysis and an eGFR is shown, ignore it.

Different ways of calculating eGFR. There are now two different methods to calculate eGFR. The MDRD method is still more common, but the CKD-EPI method is growing. The two methods give similar results when kidney function is poor, but CKD-EPI results tend to be higher, and more accurate, in people with quite good kidney function (especially over 60). It isn't easy to tell what method has been used, but different methods could explain changes in eGFR when Creatinine hasn't changed much.

over 90
This may be slightly reduced, but because eGFR is only an estimate of kidney function, many people with eGFR 60-90 are normal. An eGFR of 60-90 should only be used as evidence of kidney disease if there are other things wrong - such as protein or blood on urine tests, or other tests showing kidney disease - or if it is a big change from a previous eGFR.
Moderately severe kidney damage. This is known as Stage 3 CKD
Severe kidney damage, Stage 4 CKD. Anaemia and bone disease become common problems as kidney function drops below eGFR 25.
below 15
This is known as Stage 5 CKD. An average figure for commencing dialysis in the UK is 8 to 10, but this varies a lot - lower in some people, higher in others.

eGFR is only reliable in patients who are reasonably well, and not in hospital. Even then it may be quite inaccurate in some people - usually people with much more or much less muscle than usual. So it will be misleading in people with paralysis, or who have lost a leg, or who have lost a lot of weight (muscle).

More info about eGFR from the National Kidney Federation

More info about the stages of kidney disease from EdREN

This page created 24th October 2006, last modified July 7, 2015, on the PatientView website