.gfr-calculator-container {
font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
max-width: 700px;
margin: 20px auto;
padding: 25px;
border: 1px solid #e0e0e0;
border-radius: 10px;
background-color: #fdfdfd;
box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
}
.gfr-calculator-container h2 {
color: #2c3e50;
text-align: center;
margin-bottom: 25px;
font-size: 1.8em;
}
.gfr-calculator-container .input-group {
margin-bottom: 18px;
display: flex;
flex-direction: column;
}
.gfr-calculator-container label {
display: block;
margin-bottom: 8px;
color: #34495e;
font-weight: bold;
font-size: 0.95em;
}
.gfr-calculator-container input[type="number"],
.gfr-calculator-container select {
width: calc(100% – 20px);
padding: 12px;
border: 1px solid #ccc;
border-radius: 6px;
font-size: 1em;
box-sizing: border-box;
transition: border-color 0.3s ease;
}
.gfr-calculator-container input[type="number"]:focus,
.gfr-calculator-container select:focus {
border-color: #007bff;
outline: none;
box-shadow: 0 0 5px rgba(0, 123, 255, 0.2);
}
.gfr-calculator-container .radio-group {
display: flex;
gap: 20px;
margin-top: 5px;
margin-bottom: 10px;
}
.gfr-calculator-container .radio-group label {
font-weight: normal;
margin-bottom: 0;
display: flex;
align-items: center;
cursor: pointer;
}
.gfr-calculator-container .radio-group input[type="radio"] {
margin-right: 8px;
transform: scale(1.1);
}
.gfr-calculator-container button {
width: 100%;
padding: 14px;
background-color: #007bff;
color: white;
border: none;
border-radius: 6px;
font-size: 1.1em;
font-weight: bold;
cursor: pointer;
transition: background-color 0.3s ease, transform 0.2s ease;
margin-top: 20px;
}
.gfr-calculator-container button:hover {
background-color: #0056b3;
transform: translateY(-1px);
}
.gfr-calculator-container .result-section {
margin-top: 30px;
padding: 20px;
background-color: #e9f7ef;
border: 1px solid #d4edda;
border-radius: 8px;
text-align: center;
font-size: 1.1em;
color: #155724;
display: none; /* Hidden by default */
}
.gfr-calculator-container .result-section p {
margin: 8px 0;
line-height: 1.6;
}
.gfr-calculator-container .result-section strong {
color: #004085;
}
.gfr-calculator-container .error-message {
color: #dc3545;
margin-top: 15px;
text-align: center;
font-weight: bold;
display: none;
}
.gfr-calculator-container .article-content {
margin-top: 40px;
line-height: 1.7;
color: #333;
font-size: 1em;
}
.gfr-calculator-container .article-content h3 {
color: #2c3e50;
margin-top: 30px;
margin-bottom: 15px;
font-size: 1.5em;
}
.gfr-calculator-container .article-content p {
margin-bottom: 15px;
}
.gfr-calculator-container .article-content ul {
list-style-type: disc;
margin-left: 20px;
margin-bottom: 15px;
}
.gfr-calculator-container .article-content li {
margin-bottom: 8px;
}
.gfr-calculator-container .disclaimer {
margin-top: 30px;
padding: 15px;
background-color: #fff3cd;
border: 1px solid #ffeeba;
border-radius: 8px;
color: #856404;
font-size: 0.9em;
text-align: center;
}
function calculateGFR() {
var creatinine = parseFloat(document.getElementById('creatinine').value);
var age = parseInt(document.getElementById('age').value);
var sexMale = document.getElementById('sexMale').checked;
var raceBlack = document.getElementById('raceBlack').checked;
var errorMessageDiv = document.getElementById('errorMessage');
var gfrResultSection = document.getElementById('gfrResultSection');
errorMessageDiv.style.display = 'none';
gfrResultSection.style.display = 'none';
if (isNaN(creatinine) || creatinine <= 0 || isNaN(age) || age 120) {
errorMessageDiv.textContent = 'Please enter valid positive numbers for Serum Creatinine (mg/dL) and Age (18-120 years).';
errorMessageDiv.style.display = 'block';
return;
}
var kappa, alpha, sexFactor;
if (sexMale) {
kappa = 0.9;
alpha = -0.411;
sexFactor = 1;
} else { // Female
kappa = 0.7;
alpha = -0.329;
sexFactor = 1.018;
}
var gfr;
var scr_over_kappa = creatinine / kappa;
if (scr_over_kappa = 90) {
gfrStageText = 'Stage 1: Normal kidney function (with other signs of kidney damage)';
} else if (gfr >= 60) {
gfrStageText = 'Stage 2: Mildly decreased kidney function (with other signs of kidney damage)';
} else if (gfr >= 45) {
gfrStageText = 'Stage 3a: Mild to moderate decrease in kidney function';
} else if (gfr >= 30) {
gfrStageText = 'Stage 3b: Moderate to severe decrease in kidney function';
} else if (gfr >= 15) {
gfrStageText = 'Stage 4: Severely decreased kidney function';
} else {
gfrStageText = 'Stage 5: Kidney failure (End-Stage Renal Disease)';
}
document.getElementById('gfrStage').textContent = gfrStageText;
gfrResultSection.style.display = 'block';
}
GFR Kidney Function Calculator
Your Estimated GFR: mL/min/1.73m²
Kidney Disease Stage:
Understanding Your Glomerular Filtration Rate (GFR)
The Glomerular Filtration Rate (GFR) is a crucial measure of kidney function. It estimates how much blood passes through the glomeruli each minute. Glomeruli are tiny filters in your kidneys that remove waste products and excess water from your blood. A healthy GFR indicates that your kidneys are effectively cleaning your blood.
Why is GFR Important?
Monitoring your GFR is vital for detecting and managing kidney disease. A declining GFR can be an early sign of chronic kidney disease (CKD), which, if left untreated, can progress to kidney failure. Early detection allows for interventions that can slow the progression of the disease and prevent serious complications.
- Early Detection: Identifies kidney problems before symptoms appear.
- Disease Staging: Helps classify the stage of kidney disease, guiding treatment.
- Treatment Planning: Informs decisions about medications, diet, and lifestyle changes.
- Monitoring Progression: Tracks the effectiveness of treatments over time.
How is GFR Calculated?
Directly measuring GFR is complex and usually involves injecting a tracer substance. Therefore, GFR is most commonly estimated using formulas that incorporate readily available blood test results and patient characteristics. This calculator uses the CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) 2009 equation, which is widely accepted and considered more accurate than older formulas like MDRD.
The CKD-EPI 2009 formula takes into account:
- Serum Creatinine (mg/dL): Creatinine is a waste product from muscle metabolism. Healthy kidneys filter creatinine efficiently, so high levels in the blood can indicate impaired kidney function.
- Age (years): Kidney function naturally declines with age.
- Sex: Biological differences between males and females affect creatinine levels and kidney function.
- Race (Black/Non-Black): Historically, race has been included in GFR equations due to observed differences in average creatinine levels. However, there's an ongoing discussion in the medical community about the implications of including race, and newer formulas are being developed that do not use this factor. For this calculator, we use the CKD-EPI 2009 formula which includes it.
Interpreting Your GFR Results (CKD Stages)
The GFR value helps classify the stage of chronic kidney disease:
- Stage 1: GFR ≥ 90 mL/min/1.73m² – Normal kidney function, but with other signs of kidney damage (e.g., protein in urine).
- Stage 2: GFR 60-89 mL/min/1.73m² – Mildly decreased kidney function, with other signs of kidney damage.
- Stage 3a: GFR 45-59 mL/min/1.73m² – Mild to moderate decrease in kidney function.
- Stage 3b: GFR 30-44 mL/min/1.73m² – Moderate to severe decrease in kidney function.
- Stage 4: GFR 15-29 mL/min/1.73m² – Severely decreased kidney function.
- Stage 5: GFR < 15 mL/min/1.73m² – Kidney failure (End-Stage Renal Disease), often requiring dialysis or kidney transplant.
A GFR below 60 mL/min/1.73m² for three months or more is a key indicator of chronic kidney disease.
Disclaimer: This GFR calculator provides an estimate based on the CKD-EPI 2009 formula and should not be used as a substitute for professional medical advice. Always consult with a qualified healthcare provider for diagnosis, treatment, and interpretation of your health results.