Egfr Calculator

eGFR Calculator (CKD-EPI 2021)

Use this calculator to estimate your Glomerular Filtration Rate (eGFR) based on your serum creatinine, age, and sex, using the CKD-EPI 2021 equation.

function calculateEgfr() { var serumCreatinine = parseFloat(document.getElementById('serumCreatinine').value); var age = parseInt(document.getElementById('age').value); var sexMale = document.getElementById('sexMale').checked; var sexFemale = document.getElementById('sexFemale').checked; if (isNaN(serumCreatinine) || serumCreatinine <= 0) { document.getElementById('egfrResult').innerHTML = 'Please enter a valid Serum Creatinine value (e.g., 0.9).'; return; } if (isNaN(age) || age 120) { document.getElementById('egfrResult').innerHTML = 'Please enter a valid Age between 18 and 120 years.'; return; } if (!sexMale && !sexFemale) { document.getElementById('egfrResult').innerHTML = 'Please select your Sex.'; return; } var kappa, alpha, sexFactor; if (sexFemale) { kappa = 0.7; alpha = -0.241; sexFactor = 1.012; } else { // Male kappa = 0.9; alpha = -0.302; sexFactor = 1; } var minScrOverKappa = Math.min(serumCreatinine / kappa, 1); var maxScrOverKappa = Math.max(serumCreatinine / kappa, 1); var egfr = 142 * Math.pow(minScrOverKappa, alpha) * Math.pow(maxScrOverKappa, -1.200) * Math.pow(0.9938, age) * sexFactor; var resultHtml = '

Your Estimated GFR (eGFR):

'; resultHtml += " + egfr.toFixed(0) + ' mL/min/1.73m2'; var stage = "; var recommendation = "; if (egfr >= 90) { stage = 'G1 (Normal or High)'; recommendation = 'Kidney function is normal or high. Continue routine check-ups.'; } else if (egfr >= 60) { stage = 'G2 (Mildly Decreased)'; recommendation = 'Kidney function is mildly decreased. Monitor regularly and discuss with your doctor.'; } else if (egfr >= 45) { stage = 'G3a (Mildly to Moderately Decreased)'; recommendation = 'Kidney function is mildly to moderately decreased. Consult your doctor for management.'; } else if (egfr >= 30) { stage = 'G3b (Moderately to Severely Decreased)'; recommendation = 'Kidney function is moderately to severely decreased. Close medical follow-up is recommended.'; } else if (egfr >= 15) { stage = 'G4 (Severely Decreased)'; recommendation = 'Kidney function is severely decreased. Prepare for kidney failure and discuss treatment options with your specialist.'; } else { stage = 'G5 (Kidney Failure)'; recommendation = 'Kidney failure. Immediate medical attention and treatment (dialysis or transplant) are necessary.'; } resultHtml += 'CKD Stage: ' + stage + "; resultHtml += 'Recommendation: ' + recommendation + "; resultHtml += 'This calculation uses the CKD-EPI 2021 equation and is for informational purposes only. It should not replace professional medical advice. Always consult with a healthcare provider for diagnosis and treatment.'; document.getElementById('egfrResult').innerHTML = resultHtml; } .egfr-calculator-container { font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif; background-color: #f9f9f9; border: 1px solid #ddd; border-radius: 8px; padding: 25px; max-width: 600px; margin: 20px auto; box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08); color: #333; } .egfr-calculator-container h2 { color: #2c3e50; text-align: center; margin-bottom: 20px; font-size: 1.8em; } .egfr-calculator-container p { line-height: 1.6; margin-bottom: 15px; } .calculator-form .form-group { margin-bottom: 18px; } .calculator-form label { display: block; margin-bottom: 8px; font-weight: bold; color: #555; } .calculator-form input[type="number"], .calculator-form input[type="text"] { width: calc(100% – 22px); padding: 12px; border: 1px solid #ccc; border-radius: 5px; font-size: 1em; box-sizing: border-box; } .calculator-form input[type="radio"] { margin-right: 8px; vertical-align: middle; } .calculator-form input[type="radio"] + label { display: inline-block; margin-right: 20px; font-weight: normal; } .calculator-form button { background-color: #3498db; color: white; padding: 12px 25px; border: none; border-radius: 5px; cursor: pointer; font-size: 1.1em; display: block; width: 100%; margin-top: 25px; transition: background-color 0.3s ease; } .calculator-form button:hover { background-color: #2980b9; } .result-container { background-color: #eaf4f9; border: 1px solid #b3d9ee; border-radius: 8px; padding: 20px; margin-top: 30px; font-size: 1.1em; color: #2c3e50; } .result-container h3 { color: #2c3e50; margin-top: 0; margin-bottom: 15px; font-size: 1.5em; text-align: center; } .result-container p { margin-bottom: 10px; } .result-container .egfr-value { font-size: 2em; font-weight: bold; color: #27ae60; text-align: center; margin-bottom: 20px; } .result-container .disclaimer { font-size: 0.9em; color: #777; margin-top: 20px; border-top: 1px dashed #ccc; padding-top: 15px; }

Understanding Your eGFR: A Key Indicator of Kidney Health

The Estimated Glomerular Filtration Rate (eGFR) is a crucial measure used by healthcare professionals to assess kidney function. It indicates how well your kidneys are filtering waste products from your blood. A healthy eGFR means your kidneys are working efficiently, while a lower eGFR can signal kidney damage or disease.

What is GFR and Why is it Important?

The Glomerular Filtration Rate (GFR) measures the flow rate of filtered fluid through the kidney. Essentially, it tells us how many milliliters of blood your kidneys filter per minute. Since directly measuring GFR is complex and invasive, doctors typically rely on eGFR, which is estimated using a formula based on readily available blood test results and patient characteristics.

Monitoring eGFR is vital for:

  • Detecting Kidney Disease Early: Early detection allows for interventions that can slow the progression of kidney disease.
  • Staging Chronic Kidney Disease (CKD): eGFR values are used to classify CKD into different stages, guiding treatment plans.
  • Monitoring Disease Progression: Tracking changes in eGFR over time helps assess the effectiveness of treatments and the progression of kidney damage.
  • Medication Dosing: Many medications are cleared by the kidneys, and their dosages may need adjustment based on eGFR to prevent accumulation and toxicity.

How is eGFR Calculated? The CKD-EPI 2021 Equation

Several formulas exist to estimate GFR, but the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations are widely used. Our calculator utilizes the CKD-EPI 2021 equation, which is a significant advancement as it removes the race variable from the calculation. This change addresses concerns about health disparities and provides a more equitable assessment of kidney function for all individuals.

The CKD-EPI 2021 equation uses:

  • Serum Creatinine (Scr): A waste product from muscle metabolism, measured in a blood test.
  • Age: Kidney function naturally declines with age.
  • Sex: Biological sex influences muscle mass and creatinine levels.

By combining these factors, the formula provides an estimate of your kidney's filtering capacity, expressed in milliliters per minute per 1.73 square meters of body surface area (mL/min/1.73m2).

Interpreting Your eGFR Results: CKD Stages

Your eGFR value helps classify your kidney health into stages of Chronic Kidney Disease (CKD):

  • eGFR 90 or higher (Stage G1): Normal or high kidney function.
  • eGFR 60-89 (Stage G2): Mildly decreased kidney function.
  • eGFR 45-59 (Stage G3a): Mildly to moderately decreased kidney function.
  • eGFR 30-44 (Stage G3b): Moderately to severely decreased kidney function.
  • eGFR 15-29 (Stage G4): Severely decreased kidney function.
  • eGFR less than 15 (Stage G5): Kidney failure.

It's important to note that an eGFR below 60 mL/min/1.73m2 for three months or more indicates chronic kidney disease. Even if your eGFR is above 60, other signs of kidney damage (like protein in urine) can also indicate CKD.

Example Calculation

Let's consider an example:

  • Serum Creatinine: 0.9 mg/dL
  • Age: 45 years
  • Sex: Female

Using the CKD-EPI 2021 formula, the eGFR for this individual would be approximately 85 mL/min/1.73m2. This falls into Stage G2, indicating mildly decreased kidney function, which warrants regular monitoring and discussion with a healthcare provider.

Limitations and What to Do Next

While eGFR is a powerful tool, it's an estimate. Factors like extreme body size, certain medications, or acute kidney injury can affect its accuracy. Always discuss your eGFR results with your doctor. They will consider your overall health, medical history, and other test results to provide a comprehensive diagnosis and personalized management plan.

This calculator is for informational purposes only and should not be used as a substitute for professional medical advice, diagnosis, or treatment.

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