Understanding Your eGFR
Glomerular Filtration Rate (GFR) is the best overall index of kidney function. However, directly measuring GFR can be complex. The eGFR is an estimate derived from blood tests (specifically, serum creatinine) and demographic factors like age and sex. It's a vital tool for detecting and monitoring chronic kidney disease (CKD).
How it works:
The CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) creatinine equation is one of the most commonly used formulas to estimate GFR. The 2021 version is an update designed to be more accurate and equitable, particularly by removing the race coefficient. The formula takes your serum creatinine level, age, and sex into account to predict how well your kidneys are filtering waste products from your blood.
Interpreting Your eGFR:
- eGFR of 90 or higher: Generally considered normal kidney function.
- eGFR between 60 and 89: May indicate mild kidney damage, but can also be normal for some older adults. Further evaluation is often recommended.
- eGFR below 60: Indicates moderate to severe kidney damage and is a sign of Chronic Kidney Disease (CKD). The lower the number, the more severe the kidney disease.
- eGFR below 15: Indicates kidney failure, requiring dialysis or a kidney transplant.
Disclaimer: This calculator is for informational purposes only and should not be considered a substitute for professional medical advice. Always consult with a qualified healthcare provider for any health concerns or before making any decisions related to your health or treatment.
function calculateeGFR() {
var serumCreatinine = parseFloat(document.getElementById("serumCreatinine").value);
var age = parseInt(document.getElementById("age").value);
var sex = document.getElementById("sex").value;
var resultDiv = document.getElementById("result");
resultDiv.innerHTML = ""; // Clear previous results
if (isNaN(serumCreatinine) || serumCreatinine <= 0) {
resultDiv.innerHTML = "Please enter a valid serum creatinine level.";
return;
}
if (isNaN(age) || age <= 0) {
resultDiv.innerHTML = "Please enter a valid age.";
return;
}
var sexFactor;
if (sex === "male") {
sexFactor = 1.018;
} else {
sexFactor = 0.975;
}
// CKD-EPI 2021 formula for creatinine
// Reference: Inker LA, et al. NEJM 2021;385:1737-1747.
// For serum creatinine (SCr) in mg/dL
var egfr;
var sr = serumCreatinine; // Shortened for formula
var a = -0.241; // For males
var b = 0.993; // For females
if (sex === "male") {
if (sr <= 0.7) {
egfr = 133 * Math.pow(sr / 0.7, a) * Math.pow(0.993, age);
} else {
egfr = 133 * Math.pow(sr / 0.7, -1.200) * Math.pow(0.993, age);
}
} else { // Female
if (sr 0.7 mg/dL (males) or SCr > 0.5 mg/dL (females):
// eGFR = 133 × (SCr/0.7)^(-1.200) × (0.993)^Age (males)
// eGFR = 166 × (SCr/0.5)^(-1.153) × (0.993)^Age (females)
var egfr_val;
if (sex === "male") {
if (serumCreatinine <= 0.7) {
egfr_val = 133 * Math.pow(serumCreatinine / 0.7, -0.241) * Math.pow(0.993, age);
} else {
egfr_val = 133 * Math.pow(serumCreatinine / 0.7, -1.200) * Math.pow(0.993, age);
}
} else { // Female
if (serumCreatinine <= 0.5) {
egfr_val = 166 * Math.pow(serumCreatinine / 0.5, -0.241) * Math.pow(0.993, age);
} else {
egfr_val = 166 * Math.pow(serumCreatinine / 0.5, -1.153) * Math.pow(0.993, age);
}
}
// eGFR values are typically rounded to the nearest whole number.
var finalEGFR = Math.round(egfr_val);
resultDiv.innerHTML = "Your Estimated Glomerular Filtration Rate (eGFR) is:
" + finalEGFR + " mL/min/1.73m²";
if (finalEGFR = 60 && finalEGFR < 90) {
resultDiv.innerHTML += "This may indicate mild kidney damage or be normal for age. Consult your doctor for evaluation.";
} else {
resultDiv.innerHTML += "Your eGFR is generally considered normal.";
}
}
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flex-wrap: wrap;
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margin-bottom: 30px;
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