LDL (Low-Density Lipoprotein) cholesterol, often referred to as "bad" cholesterol, plays a crucial role in cardiovascular health. High levels of LDL can lead to the buildup of plaque in arteries, increasing the risk of heart disease and stroke. While direct measurement of LDL is the most accurate, a common and widely used method is to estimate it using the Friedewald equation, especially when triglycerides are within a certain range.
The Friedewald Equation
The Friedewald equation is a formula used to estimate LDL cholesterol levels based on measurements of total cholesterol, HDL cholesterol, and triglycerides. The formula is as follows:
This equation is most accurate when triglyceride levels are below 400 mg/dL. For triglyceride levels at or above 400 mg/dL, this estimation method becomes unreliable, and a direct LDL measurement (e.g., by ultracentrifugation or selective B-apolipoprotein precipitation) is recommended by healthcare professionals.
How the Calculator Works
Total Cholesterol: This is the sum of all cholesterol in your blood, including LDL, HDL, and other lipid components.
HDL Cholesterol: High-Density Lipoprotein (HDL) cholesterol is known as "good" cholesterol because it helps remove LDL cholesterol from the arteries.
Triglycerides: These are a type of fat found in your blood. High levels of triglycerides, especially when combined with high LDL or low HDL, are linked to an increased risk of heart disease.
The calculator takes these three values and applies the Friedewald equation to provide an estimated LDL cholesterol level.
Interpreting Your Results
After calculating your estimated LDL cholesterol, it's important to discuss the results with your healthcare provider. Generally, desirable LDL levels are considered to be:
Optimal: Less than 100 mg/dL
Near Optimal/Above Average: 100-129 mg/dL
Borderline High: 130-159 mg/dL
High: 160-189 mg/dL
Very High: 190 mg/dL and above
Remember, these are general guidelines. Your specific target LDL level may vary based on your individual risk factors for heart disease, such as age, family history, diabetes, blood pressure, and smoking status. This calculator is intended for informational purposes only and does not substitute professional medical advice. Always consult with a qualified healthcare professional for any health concerns or before making any decisions related to your health or treatment.
function calculateLDL() {
var totalCholesterol = parseFloat(document.getElementById("totalCholesterol").value);
var hdlCholesterol = parseFloat(document.getElementById("hdlCholesterol").value);
var triglycerides = parseFloat(document.getElementById("triglycerides").value);
var resultDiv = document.getElementById("result");
var errorMessage = "";
if (isNaN(totalCholesterol) || totalCholesterol <= 0) {
errorMessage += "Please enter a valid Total Cholesterol value.";
}
if (isNaN(hdlCholesterol) || hdlCholesterol <= 0) {
errorMessage += "Please enter a valid HDL Cholesterol value.";
}
if (isNaN(triglycerides) || triglycerides = 400) {
resultDiv.innerHTML = "Triglycerides are too high (>= 400 mg/dL) for accurate Friedewald calculation. Please consult your doctor for a direct LDL measurement.";
resultDiv.style.color = "#ffc107"; // Warning color
return;
}
var estimatedLDL = totalCholesterol – hdlCholesterol – (triglycerides / 5);
// Ensure calculated LDL is not negative, which can happen with very high HDL/Triglycerides relative to Total
if (estimatedLDL < 0) {
estimatedLDL = 0;
}
resultDiv.innerHTML = "Estimated LDL Cholesterol: " + estimatedLDL.toFixed(2) + " mg/dL";
resultDiv.style.color = "#28a745"; // Success color
}