eGFR calculator

Your kidneys are made up of thousands of tiny filters called Nephrons. Your kidney function is determined by how well these filters are working. The filters in your kidney work much the same way that a water filter works - they clean your blood by removing the waste products that then leave the body via the urine, and they return the clean blood to keep circulating around your body.

The degree to which your kidneys are working and filtering your blood is measured by your Glomerular Filtration Rate or GFR. You GFR is very difficult to measure in the body, so it is calculated using an equation. The equation uses the amount of Creatinine (a waste product) in your blood, as well as your sex and age to work out an estimated GFR (eGFR).

Your eGFR is roughly equivalent to the degree of kidney function you have, so an eGFR of 60 would mean that your kidneys are only working at about 60%. eGFR is the best measure of how well your kidneys are working and in Australia, these results are reported on blood test results for individuals aged 18 years and over.

Your GP of Nephrologist will monitor your eGFR regularly, as a declining eGFR is a sign that your kidney disease is getting worse.

For more information about eGFR and what your eGFR number mean, please refer to our eGFR fact sheet.

A value below 60mL/min/1.73m2 suggests some loss of kidney function. If this is the case, retest your patient within seven days and consider clinical situations in which eGFR results may be unreliable and/or misleading, as well as acute kidney damage.

Chronic kidney disease is diagnosed when eGFR results are consistently less than 60mL/min/1.73m2 for more than three months (with or without evidence of kidney damage).

Chronic kidney disease may also be diagnosed when there is evidence of kidney damage (with or without decreased eGFR) that is present for three months of more. Kidney damage is evidenced by:

• albuminuria
• haematuria after exclusion of urological causes
• structural abnormalities (e.g. identified on kidney imaging tests)
• pathological abnormalities (e.g. identified on a renal biopsy).

For more detailed information designed for health professionals, you can read our Chronic Kidney Disease Management in Primary Care handbook. It provides guidance and clinical tips that help you detect, manage and refer patients with chronic kidney disease.