Creatinine and eGFR — Kidney Function
Serum creatinine and the calculated eGFR estimate the kidney filtration rate. Creatinine varies with muscle mass, so read the result in that context.
Serum creatinine and the calculated eGFR estimate the rate at which your kidneys filter blood, the core measure of kidney function. Creatinine levels vary with body size and muscle mass, so read the result in that context.
Watch the 39-second version
If you lift, your creatinine can read high without your kidneys being in any trouble.
Transcript & sources → All videosMr. Age is AgeGen's editorial character. Facts come from the protocol above.
The biomarker
- Name: Creatinine + eGFR
- Units: Creatinine mg/dL; eGFR mL/min/1.73m²
- Standard reference range: Creatinine 0.7–1.3 mg/dL (men), 0.5–0.95 mg/dL (women); an eGFR of 60 or more is in the normal range (ranges vary by lab)
How to read your result
| Value (mL/min/1.73m²) | Interpretation |
|---|---|
| eGFR 90–120 | Normal kidney function (NIDDK) |
| eGFR 60–89 | Mild decrease in function (NIDDK) — ask your clinician whether to recheck and add a urine ACR |
| eGFR 15–59 | Moderate to severe decrease in function (NIDDK) — see a clinician |
| eGFR < 15 | Kidney failure (NIDDK) — needs prompt clinician care |
What to ask about
- Testing. Ask whether a urine albumin-to-creatinine ratio (UACR) should be added — eGFR and urine albumin are the two key markers for kidney disease.
- Medication. Regular use of NSAIDs such as ibuprofen and naproxen can damage the kidneys — ask your pharmacist or clinician whether the medicines you take are safe for you.
Why this test is worth asking for
- eGFR estimates kidney filtration rate from a single blood draw; an eGFR below 60 may mean kidney disease.
- Creatinine varies with muscle mass, so the number is read in the context of your body size and build.
- eGFR and urine albumin are the two key markers for kidney disease, which is why the two are often read together.
Related protocols
- Urine ACR — Albumin-to-Creatinine Kidney Marker
- Uric Acid — Metabolic + Gout Marker
- HbA1c — Three-Month Glucose Average
Sources
- MedlinePlus — Creatinine Test
- MedlinePlus — Creatinine blood test
- NIDDK — Chronic kidney disease tests and diagnosis
- NIDDK — Explaining your kidney test results
- NIDDK — Keeping kidneys safe: smart choices about medicines
AgeGen lab guides are educational only. We do not provide medical diagnosis, prescribe brands, or recommend specific doses. Talk to a licensed clinician before changing your supplement or medication routine.
