If you have diabetes, high blood pressure, or a family history of kidney disease, these two blood tests are how we find out whether your kidneys are struggling — often years before you would feel anything.
What these tests measure
Creatinine is a waste product your muscles make every day. Healthy kidneys clear it from your blood at a steady rate. When kidney function drops, creatinine rises.
On its own, creatinine is a blunt instrument. A muscular 30-year-old and a frail 80-year-old can have the same creatinine and very different kidney function. That is why we calculate eGFR — estimated glomerular filtration rate — which adjusts the creatinine result for your age and sex to estimate how many milliliters of blood your kidneys filter each minute.
What your eGFR means
A normal eGFR is above 90. Below 60, sustained for three months or longer, meets the definition of chronic kidney disease.
- 90 or above — normal filtration
- 60 to 89 — mildly reduced; often normal for age
- 45 to 59 — Stage 3a chronic kidney disease
- 30 to 44 — Stage 3b
- 15 to 29 — Stage 4; time to plan for kidney replacement therapy
- Below 15 — Stage 5, kidney failure
A single low result does not make a diagnosis. Dehydration, a recent illness, or certain medications can push creatinine up temporarily. We look at the trend across repeated tests.
| Test | What it tells us |
|---|---|
| eGFR | How much filtering capacity remains |
| Urine albumin (ACR) | Whether the filters are leaking protein |
| Creatinine | The blood marker eGFR is calculated from |
What happens at your visit
A standard blood draw. No fasting is required, and results are usually back within a day.
We pair the eGFR with a urine albumin-to-creatinine ratio, because kidney damage and kidney function are two different things. It is entirely possible to have a normal eGFR and significant protein leaking into the urine — that combination changes both your prognosis and your treatment.
Why this matters early
Early chronic kidney disease has no symptoms. By the time swelling, fatigue, or foamy urine appear, substantial function has usually been lost. Testing catches it while there is still a great deal we can do — blood pressure control, SGLT2 inhibitors, ACE inhibitors or ARBs, and medication adjustments that meaningfully slow or halt progression.