Estimated glomerular filtration rate
To determine the function of your kidneys. The GFR (glomerular filtration rate) is the best marker of kidney function, however it is not routinely performed. Instead an estimated GFR (eGFR) is calculated using your age, gener, and serum creatinine level. The calculated result is usually included on the pathology report with every request for a creatinine in adults.
To look for evidence of kidney damage or to monitor changes in kidney function if you already have kidney disease.
A blood sample drawn from a vein in your arm.
The glomerular filtration rate (GFR) is a measure of the function of your kidneys. Glomeruli are tiny filters in your kidney that allow waste products to be removed from the blood, while preventing loss of important proteins and blood cells. The rate refers to the amount of blood that is filtered per minute.
A blood sample is taken by needle from a vein in the arm: your sex and age are taken from the patient details on your pathology request form.
eGFR is very accurate and convenient way to detect changes in kidney function. If kidney damage is detected early, it may be possible to prevent further damage by treatment of high blood pressure, diabetes, or other diseases that can damage the kidney. Your doctor may also need to know your eGFR before prescribing certain medications, because you may need a lower dose than usual if you have kidney damage. eGFR is based on serum creatinine, an easily performed and commonly measured laboratory test.
eGFR is routinely offered by the majority of Australian laboratories. It has been introduced to improve the detection of early kidney damage so that measures can be taken to stop, or at least slow progression to more severe kidney damage. eGFR is suitable for most patients who are 18 years or older, not pregnant or malnourished and do not have acute kidney damage. Doctors and laboratories are now using eGFR to look for the presence of kidney damage in various 'at risk groups' including people with: diabetes, blood vessel disease, heart problems, high blood pressure, obstructions to urine flow, and in patients taking some commonly prescribed drugs including diuretics (water tablets) and a variety of drugs used to treat high blood pressure.
eGFR is a simple test to detect early changes in kidney function. A normal result means that kidney disease is less likely while a low value indicates that some kidney damage has occurred. Most severe kidney damage leads to progressively lower eGFR values. Sometimes, in very early kidney damage (especially when the kidneys are damaged by diabetes), other tests such as protein urine or microalbumin may show kidney damage before any change in the eGFR.
A recent meal of cooked meat can increase the measurement of serum creatinine and falsely lower the eGFR.
As creatinine levels are inluenced by muscle mass eGFR may be an unreliable indicator of kidney function in those with muscle mass that varies greatly from the average adult, e.g. the frail and elderly or bodybuilders.
creatinine, creatinine urine, microalbumin,
cystatin C, protein urine
Conditions: Kidney disease
Kidney Health Australia
Australasian eGFR formula from the Australasian Creatinine Consensus Working Group
Position Statement. Source: MJA 2007; 187: 459-463 (pdf)
Online eGFR calculator (using the CKD-EPI formula)
RCPA Manual - eGFR
Last Review Date: April 1, 2021