What is GFR?
Glomerular Filtration Rate (GFR) measures how well your kidneys filter blood. It's the best overall indicator of kidney function. Normal GFR is 90-120 ml/min/1.73m². GFR below 60 for 3+ months indicates chronic kidney disease (CKD).
CKD Stages
G1 (≥90): Normal kidney function, may have other signs of kidney damage
G2 (60-89): Mildly reduced function
G3a (45-59): Mild-moderately reduced
G3b (30-44): Moderate-severely reduced
G4 (15-29): Severely reduced, plan for dialysis
G5 (<15): Kidney failure, dialysis or transplant needed
Important Notes
This calculator uses the CKD-EPI equation (2009), currently recommended over MDRD. eGFR is an estimate; actual GFR requires 24-hour urine collection. Creatinine can be affected by muscle mass, diet, and medications. One abnormal result doesn't mean CKD; repeat testing needed. Consult nephrologist if eGFR <45 or declining rapidly.
Quick Tips
- BMI alone doesn't reflect overall health
- TDEE varies based on activity level
- Consult a healthcare professional for medical decisions
Frequently Asked Questions
Diabetes, high blood pressure, glomerulonephritis, polycystic kidney disease, prolonged NSAID use, aging.
Sometimes, if caused by reversible factors (dehydration, certain medications). CKD is usually progressive.
Moderate protein restriction (0.8g/kg) may help in advanced CKD. Discuss with nephrologist.
Usually when GFR <15 (stage G5) and/or symptoms of kidney failure appear.
Yes, GFR declines about 1ml/min/year after age 40. But many maintain >60 into old age.