Creatinine and eGFR are related kidney tests, but one result does not by itself establish chronic kidney disease. The trend over time, urine albumin results, and the clinical context matter.
What do these tests measure?
Serum creatinine is a waste product influenced partly by muscle metabolism and cleared by the kidneys. eGFR (estimated glomerular filtration rate) uses creatinine with demographic variables to estimate kidney filtration. Current adult guidance supports race-free equations such as the 2021 CKD-EPI creatinine equation.
Common units
- Creatinine: mg/dL or µmol/L
- eGFR: mL/min/1.73 m²
Laboratory reference information can vary. eGFR should not be interpreted as a stand-alone diagnosis.
Why does persistence matter?
Chronic kidney disease requires evidence of reduced kidney function or kidney damage that is persistent, generally for at least three months. An eGFR below 60 mL/min/1.73 m² that persists is important, but kidney damage such as albuminuria can also matter when eGFR is higher. Acute illness, dehydration, rapidly changing creatinine, and other situations can make a single estimate less reliable.
What else should you look at?
- Previous creatinine and eGFR values
- Urine albumin-creatinine ratio (uACR) or other urine protein testing
- Blood pressure, diabetes, and other kidney-risk conditions
- Recent acute illness, dehydration, or major changes in muscle mass
When a creatinine-only estimate may be inaccurate or the value is close to an important decision threshold, an estimate using both creatinine and cystatin C may improve accuracy.
Related tools
For established CKD G3–G5 with eGFR and urine ACR, the KFRE kidney failure risk calculator estimates 2- and 5-year treated kidney failure risk. Review the result with trends and disease context.
The Life Choice Note eGFR calculator uses the 2021 CKD-EPI creatinine equation for general information. If you have albumin and creatinine concentrations from the same urine sample, the urine ACR calculator can show their ratio. Do not use a single calculator result to diagnose CKD or change a medicine dose on your own.
Questions to discuss at an appointment
- Has this value changed meaningfully from my previous results?
- Should I also have a urine albumin test?
- Could an acute illness or dehydration have affected this result?
- When and how should this be rechecked?
Related guides
Lab result guide · eGFR versus CrCl
Use the blood pressure and lab result log to bring dates, units, previous results and questions to your visit.
Sources and review status
NIDDK: GFR equations · KDIGO 2024 CKD guideline · Korea Disease Control and Prevention Agency: CKD. Sources checked 2026-09-25. This is general health information, not a diagnosis or treatment plan. Editorial review against official sources is complete; it has not been represented as independently physician-reviewed.