Creatinine and Calculated Glomerular Filtration Rate

eGFR Calculator (CKD-EPI 2021)

Male Female

Your Results:

Calculated eGFR: – mL/min/1.73m²

Interpretation: –

function calculateEGFR() { var scr = parseFloat(document.getElementById('creatinine').value); var age = parseInt(document.getElementById('age').value); var gender = document.getElementById('gender').value; var resultBox = document.getElementById('result-box'); var egfrValueDisplay = document.getElementById('egfr-value'); var egfrStageDisplay = document.getElementById('egfr-stage'); var egfrDescDisplay = document.getElementById('egfr-description'); if (isNaN(scr) || isNaN(age) || scr <= 0 || age = 90) { stage = "Stage 1 (Normal)"; desc = "Your eGFR suggests normal kidney function. If there is known kidney damage (proteinuria), it is considered Stage 1 CKD."; } else if (egfr >= 60) { stage = "Stage 2 (Mildly Decreased)"; desc = "This level is normal for many people unless there are other signs of kidney damage. Consistent results between 60-89 may indicate early stage kidney disease."; } else if (egfr >= 45) { stage = "Stage 3a (Mild to Moderate Decreased)"; desc = "This indicates a mild to moderate decrease in kidney function. Consult a physician to monitor your kidney health."; } else if (egfr >= 30) { stage = "Stage 3b (Moderate to Severe Decreased)"; desc = "This indicates a moderate to severe decrease in kidney function. Professional medical monitoring is necessary."; } else if (egfr >= 15) { stage = "Stage 4 (Severely Decreased)"; desc = "This indicates a severe decrease in kidney function. You should be under the care of a nephrologist."; } else { stage = "Stage 5 (Kidney Failure)"; desc = "This indicates very severe kidney dysfunction or kidney failure. Immediate medical intervention is required."; } egfrStageDisplay.innerText = stage; egfrDescDisplay.innerText = desc; }

Understanding Creatinine and Calculated GFR

The Estimated Glomerular Filtration Rate (eGFR) is the most reliable way to measure how well your kidneys are filtering waste products from your blood. This calculation relies on a simple blood test measuring serum creatinine, a waste product produced by muscle metabolism.

Why Is This Calculation Important?

Kidney disease often has no symptoms in its early stages. By calculating the eGFR, doctors can detect Chronic Kidney Disease (CKD) much earlier than by looking at creatinine levels alone. Because creatinine levels are influenced by muscle mass, age, and sex, the eGFR "normalizes" the result to provide a clearer picture of organ health.

The CKD-EPI 2021 Equation

This calculator uses the 2021 CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) creatinine equation. This is currently the clinical gold standard as it does not include a race coefficient, providing a more equitable and accurate assessment for all patients compared to older formulas like MDRD.

Interpreting Your Results

The eGFR is reported in mL/min/1.73m². A result of 60 or higher is generally considered in the normal range. If your result is below 60 for more than three months, it may indicate chronic kidney disease.

• Stage 1 (90+): Normal function, but signs of kidney damage may be present.
• Stage 2 (60-89): Mild loss of kidney function.
• Stage 3 (30-59): Moderate loss of kidney function.
• Stage 4 (15-29): Severe loss of kidney function.
• Stage 5 (Less than 15): Kidney failure.

Example Calculation

Consider a 55-year-old male with a serum creatinine level of 1.4 mg/dL:

1. Input: Age 55, Male, Creatinine 1.4.
2. Math: The CKD-EPI formula applies specific constants for sex and creatinine thresholds.
3. Result: The eGFR would be approximately 59 mL/min/1.73m².
4. Action: This would fall into Stage 3a, indicating the need for further clinical investigation.

Disclaimer: This tool is for informational purposes only and should not replace professional medical advice. Always discuss your lab results with a qualified healthcare provider.