.calculator-container {
background-color: #f9f9f9;
border: 1px solid #ddd;
padding: 20px;
border-radius: 8px;
max-width: 600px;
margin: 20px auto;
font-family: Arial, sans-serif;
}
.calculator-input label {
display: block;
margin-bottom: 5px;
font-weight: bold;
}
.calculator-input input[type="number"] {
width: calc(100% – 12px);
padding: 8px;
margin-bottom: 15px;
border: 1px solid #ccc;
border-radius: 4px;
}
.calculator-input input[type="radio"] {
margin-right: 5px;
}
.calculator-input label[for="sexMale"],
.calculator-input label[for="sexFemale"] {
display: inline-block;
margin-right: 15px;
font-weight: normal;
}
.calculator-container button {
background-color: #007bff;
color: white;
padding: 10px 15px;
border: none;
border-radius: 4px;
cursor: pointer;
font-size: 16px;
}
.calculator-container button:hover {
background-color: #0056b3;
}
.calculator-result {
margin-top: 20px;
padding: 10px;
border: 1px solid #e0e0e0;
border-radius: 4px;
background-color: #eaf6ff;
}
.calculator-result h3 {
margin-top: 0;
color: #0056b3;
}
.calculator-result p {
margin-bottom: 0;
font-size: 0.9em;
color: #555;
}
function calculateeGFR() {
var creatinine = parseFloat(document.getElementById('creatinine').value);
var age = parseInt(document.getElementById('age').value);
var sexMale = document.getElementById('sexMale').checked;
var sexFemale = document.getElementById('sexFemale').checked;
if (isNaN(creatinine) || creatinine <= 0.01) {
document.getElementById('result').innerHTML = 'Please enter a valid Serum Creatinine value (e.g., 0.5 – 10.0 mg/dL).';
return;
}
if (isNaN(age) || age 120) {
document.getElementById('result').innerHTML = 'Please enter a valid Age (18-120 years).';
return;
}
var eGFR;
var k, alpha; // k is the threshold for creatinine, alpha is the exponent for Scr/k < 1
if (sexFemale) {
k = 0.7;
alpha = -0.241;
if (creatinine <= k) {
eGFR = 142 * Math.pow(creatinine / k, alpha) * Math.pow(0.9938, age);
} else {
eGFR = 142 * Math.pow(creatinine / k, -1.200) * Math.pow(0.9938, age);
}
} else { // Male
k = 0.9;
alpha = -0.302;
if (creatinine <= k) {
eGFR = 142 * Math.pow(creatinine / k, alpha) * Math.pow(0.9938, age);
} else {
eGFR = 142 * Math.pow(creatinine / k, -1.200) * Math.pow(0.9938, age);
}
}
document.getElementById('result').innerHTML = 'eGFR Calculator (CKD-EPI 2021)
Estimated GFR: — mL/min/1.73 m²
Enter your details and click 'Calculate eGFR'.
Estimated GFR: ' + eGFR.toFixed(2) + ' mL/min/1.73 m²
' + '(Calculated using CKD-EPI 2021 formula)'; }Understanding Your eGFR: A Key to Kidney Health
The Estimated Glomerular Filtration Rate (eGFR) is a crucial measure of how well your kidneys are functioning. It's a simple yet powerful tool used by healthcare professionals to detect, diagnose, and monitor kidney disease.What is eGFR?
Your kidneys are vital organs responsible for filtering waste products and excess water from your blood, producing urine, and maintaining a balance of electrolytes. The Glomerular Filtration Rate (GFR) is the best measure of kidney function, indicating how much blood passes through the glomeruli (tiny filters in the kidneys) each minute. Since directly measuring GFR is complex and invasive, doctors use formulas to *estimate* it based on readily available blood test results. This estimated value is known as eGFR.Why is eGFR Important?
An eGFR test is essential for:- Detecting Chronic Kidney Disease (CKD): Early detection allows for interventions that can slow the progression of kidney damage.
- Monitoring Kidney Function: For individuals already diagnosed with CKD, eGFR helps track the disease's progression and the effectiveness of treatment.
- Guiding Treatment Decisions: eGFR values influence medication dosages, dietary recommendations, and the timing of dialysis or kidney transplant evaluations.
- Assessing Overall Health: Kidney health is linked to cardiovascular health and other systemic conditions.
How is eGFR Calculated?
The eGFR calculator above uses the CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) 2021 formula. This formula is widely adopted because it provides a more accurate estimate of GFR and, importantly, does not include a race coefficient, addressing historical disparities in kidney disease diagnosis. The primary inputs for the CKD-EPI 2021 formula are:- Serum Creatinine (mg/dL): A waste product from muscle metabolism that healthy kidneys filter out of the blood. Higher creatinine levels often indicate reduced kidney function.
- Age (years): Kidney function naturally declines with age.
- Sex: Biological sex influences muscle mass and, consequently, creatinine levels.
Interpreting Your eGFR Results
eGFR is measured in milliliters per minute per 1.73 square meters (mL/min/1.73 m²), which adjusts the result for average body surface area. Here's a general guide to interpreting eGFR values:- 90 or higher: Normal kidney function.
- 60-89: Mildly decreased kidney function. This may indicate early kidney disease, especially if there are other signs of kidney damage (e.g., protein in urine).
- 45-59: Mild to moderate decrease in kidney function (CKD Stage 3a).
- 30-44: Moderate to severe decrease in kidney function (CKD Stage 3b).
- 15-29: Severely decreased kidney function (CKD Stage 4).
- Less than 15: Kidney failure (CKD Stage 5), often requiring dialysis or kidney transplant.
Factors Affecting eGFR
While creatinine, age, and sex are the primary factors in the eGFR calculation, other elements can influence your actual kidney function and the accuracy of the eGFR estimate:- Muscle Mass: Very muscular individuals or those with low muscle mass (e.g., amputees, malnourished individuals) may have creatinine levels that don't accurately reflect their kidney function.
- Diet: A high-protein diet can temporarily increase creatinine levels.
- Medications: Certain drugs can affect creatinine levels or kidney function.
- Hydration: Dehydration can temporarily elevate creatinine.
- Acute Kidney Injury: Sudden changes in kidney function may not be accurately captured by eGFR alone.
Examples of eGFR Calculation
Let's look at a few realistic scenarios using the CKD-EPI 2021 formula:- Example 1: A 45-year-old male with a serum creatinine of 1.0 mg/dL.
Calculation would yield an eGFR of approximately 89 mL/min/1.73 m². This is considered normal or mildly decreased, but warrants monitoring if other risk factors are present. - Example 2: A 60-year-old female with a serum creatinine of 0.8 mg/dL.
Calculation would yield an eGFR of approximately 78 mL/min/1.73 m². This indicates mildly decreased kidney function, which is common with age but should be monitored. - Example 3: A 70-year-old male with a serum creatinine of 1.5 mg/dL.
Calculation would yield an eGFR of approximately 48 mL/min/1.73 m². This falls into CKD Stage 3a (mild to moderate decrease), requiring medical attention and management.