Ldl Calculated

LDL Cholesterol Calculator (Friedewald Formula)

function calculateLDLValue() { var total = parseFloat(document.getElementById('totalChol').value); var hdl = parseFloat(document.getElementById('hdlChol').value); var tri = parseFloat(document.getElementById('triglycerides').value); var resultArea = document.getElementById('ldl-result-area'); var numericDisplay = document.getElementById('ldl-numeric-result'); var interpretationDisplay = document.getElementById('ldl-interpretation'); if (isNaN(total) || isNaN(hdl) || isNaN(tri) || total <= 0 || hdl <= 0 || tri = 400) { resultArea.style.display = 'block'; resultArea.style.backgroundColor = '#fff3cd'; numericDisplay.style.color = '#856404'; numericDisplay.innerHTML = 'Calculation Inaccurate'; interpretationDisplay.innerHTML = 'The Friedewald formula is not accurate when Triglycerides are 400 mg/dL or higher. A direct LDL test is recommended.'; return; } // Friedewald Formula: LDL = Total Cholesterol – HDL – (Triglycerides / 5) var ldl = total – hdl – (tri / 5); ldl = Math.round(ldl * 10) / 10; resultArea.style.display = 'block'; numericDisplay.innerHTML = 'Calculated LDL: ' + ldl + ' mg/dL'; var status = "; var bgColor = "; var textColor = "; if (ldl = 100 && ldl = 130 && ldl = 160 && ldl < 190) { status = 'High'; bgColor = '#f8d7da'; textColor = '#721c24'; } else { status = 'Very High'; bgColor = '#f8d7da'; textColor = '#721c24'; } resultArea.style.backgroundColor = bgColor; numericDisplay.style.color = textColor; interpretationDisplay.style.color = textColor; interpretationDisplay.innerHTML = 'Status: ' + status + 'Consult a physician for clinical diagnosis.'; }

Understanding Calculated LDL and the Friedewald Formula

LDL (Low-Density Lipoprotein) cholesterol is often referred to as "bad" cholesterol because high levels can lead to a buildup of plaque in your arteries, increasing the risk of heart disease and stroke. While labs can measure LDL directly, many standard lipid panels use the Friedewald Formula to provide a calculated LDL value.

How is LDL Calculated?

The Friedewald Formula is the standard mathematical method used by laboratories worldwide. It utilizes three other measured components of your lipid profile:

• Total Cholesterol: The overall amount of cholesterol in your blood.
• HDL Cholesterol: "Good" cholesterol that helps remove other forms of cholesterol.
• Triglycerides: A type of fat (lipid) found in your blood.

The Formula:
LDL = Total Cholesterol - HDL - (Triglycerides / 5)

*Note: This specific divisor (5) is for measurements in mg/dL. If using mmol/L, the divisor for triglycerides is approximately 2.2.

Clinical Interpretations of LDL Levels

Medical professionals generally categorize LDL levels based on the following mg/dL thresholds:

LDL Level (mg/dL)	Category
Less than 100	Optimal
100 – 129	Near Optimal
130 – 159	Borderline High
160 – 189	High
190 and above	Very High

Example Calculation

Suppose a patient has the following lab results:

• Total Cholesterol: 210 mg/dL
• HDL Cholesterol: 55 mg/dL
• Triglycerides: 150 mg/dL

Applying the formula: 210 - 55 - (150 / 5)
Step 1: 150 / 5 = 30
Step 2: 210 – 55 – 30 = 125 mg/dL

The patient's calculated LDL is 125 mg/dL, which falls into the "Near Optimal" category.

Limitations of the Calculated LDL Method

While convenient, the Friedewald formula has two major limitations:

1. High Triglycerides: If triglycerides are above 400 mg/dL, the formula becomes highly inaccurate and typically underestimates LDL levels.
2. Fasting State: Because triglycerides fluctuate significantly after eating, this calculation is most accurate when performed on a fasting blood sample.

If your triglyceride levels are elevated, your doctor may order a Direct LDL test, which measures the LDL particles themselves rather than estimating them through a formula.