In brief
Blood and urine tests that show how well your kidneys are clearing waste, including creatinine, eGFR, urea and the urine albumin to creatinine ratio (ACR).
What it measures
Urea and creatinine, waste products cleared by the kidneys; eGFR, an estimate of the kidneys' filtering rate calculated from creatinine, age, body size and sex; and often a urine test, including the ACR.
Why it is done
To check kidney function in conditions that affect the blood vessels, such as diabetes, high blood pressure and hardening of the arteries, and as a screen in pregnancy.
Reading the results
- An eGFR below 60 suggests that some kidney damage has occurred.
- An eGFR below 15 indicates kidney failure.
- A moderately raised ACR can indicate early kidney disease.
Reference ranges
| Result | Range |
|---|---|
| eGFR suggesting some kidney damage | Below 60 |
| eGFR indicating kidney failure | Below 15 |
Ranges differ between laboratories. Always compare a result with the range printed on your own report, and ask your doctor what it means for you.
Before the test
You may be asked to fast for 8 to 12 hours, with only water. Your doctor may also advise you not to eat a lot of meat or take creatine supplements beforehand.
What can affect the result
- Dehydration
- Muscle mass
- Large meat meals or creatine supplements
- High-protein meals (for urea)
- Some medicines
Related topics
Connections
Kidney function tests (creatinine and eGFR) measures
Creatinine, eGFR and urine tests show how well the kidneys are filtering the blood.
Sources: Pathology Tests Explained, Kidney function tests; Pathology Tests Explained, Creatinine
An eGFR below 60 suggests some kidney damage has occurred, and a moderately raised urine ACR can indicate early kidney disease.
Kidney function tests (creatinine and eGFR) is linked with
Creatine supplements taken before a blood test can cause a short-term rise in blood creatinine, which is used to estimate kidney function.
Sources: Pathology Tests Explained, Creatinine; Pathology Tests Explained, Kidney function tests
Sources
Test information summarised from the sources listed on this page, read on 19 October 2026. General education only, not medical advice. Spotted a mistake? Please tell us through the HuBu-Intel contact page.