What it measures
eGFR (estimated glomerular filtration rate) is an estimate of how much blood the kidneys filter each minute. It is not measured directly: the lab works it out from your creatinine result, age and sex.
Why people test it
- The main figure used to check kidney function and to stage chronic kidney disease.
- Checked regularly with diabetes or high blood pressure, and on medicines that affect the kidneys.
- Used to set the dose of some medicines that leave the body through the kidneys.
- Creatine use and high muscle mass raise creatinine, which pulls the eGFR figure down.
Typical range
Ranges vary between labs, with the method used, age and sex, and your report shows the lab's own range. The NHS describes an eGFR above 90 as normal. Source: NHS: chronic kidney disease, diagnosis.
Finger-prick or vein?
eGFR is worked out from the creatinine result, so it comes from the same sample. A finger-prick sample is usually fine.
Creatine raises creatinine, which can make kidney results look worse than they are. Cystatin C gives a truer read.
