At a glance

Why get tested?

To determine the function of your kidneys. The GFR (glomerular filtration rate) is the best marker of kidney function.

When to get tested?

To look for evidence of kidney damage or to monitor changes in kidney function if you already have kidney disease.

Sample required?

eGFR is calculated using your age, gender, and serum creatinine (requires a blood sample from a vein in your arm). The calculated result is usually included on the pathology report with every request for a creatinine in adults.

What is being tested?

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.

How is the sample collected for testing?

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.

The Test

How is it used?

eGFR is a most accurate, convenient way to detect changes in kidney function. If kidney damage is detected early, it may be possible to prevent further damage, with 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 used laboratory test.

When is it requested?

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 the stop, or at least slow progression to more severe kidney damage. eGFR is suitable for most patients who are 18 or more years old, 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.

What does the test result mean?

Looking for reference ranges?

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 urine protein or microalbumin may show kidney damage before any change in the eGFR.

Is there anything else I should know?

A recent meal of cooked meat can increase the measurement of serum creatinine and falsely lower the eGFR


Last Review Date: December 5, 2011