1. What is LDL Calculated?

LDL Calculated refers to the estimation of Low-Density Lipoprotein cholesterol using the Friedewald equation. This method calculates LDL-C from measured values of total cholesterol, HDL cholesterol, and triglycerides, providing an indirect measurement when direct LDL testing is not available.

2. How Does the Calculator Work?

The calculator uses the Friedewald equation:

Where:

• \( LDL-C \) — Calculated LDL cholesterol (mg/dL)
• \( TC \) — Total cholesterol (mg/dL)
• \( HDL-C \) — HDL cholesterol (mg/dL)
• \( TG \) — Triglycerides (mg/dL)

Explanation: The equation estimates LDL cholesterol by subtracting HDL cholesterol and one-fifth of triglycerides from total cholesterol, based on the assumption that VLDL cholesterol equals TG/5.

3. Importance of LDL Calculation

Details: LDL cholesterol is a major risk factor for cardiovascular disease. Accurate calculation helps assess cardiovascular risk and guide treatment decisions for cholesterol management.

4. Using the Calculator

Tips: Enter total cholesterol, HDL cholesterol, and triglycerides in mg/dL. All values must be valid (greater than 0). Note: This equation is not valid when triglycerides exceed 400 mg/dL.

5. Frequently Asked Questions (FAQ)

Q1: When is the Friedewald equation not accurate?
A: The equation becomes inaccurate when triglycerides exceed 400 mg/dL, in non-fasting samples, or in patients with dysbetalipoproteinemia.

Q2: What are the limitations of calculated LDL?
A: It assumes a fixed ratio of triglycerides to VLDL cholesterol (5:1), which may not hold true in all individuals, particularly those with hypertriglyceridemia.

Q3: When should direct LDL measurement be used instead?
A: Direct LDL measurement is preferred when triglycerides are >400 mg/dL, in non-fasting states, or when precise LDL quantification is clinically necessary.

Q4: What are optimal LDL levels?
A: Optimal LDL is <100 mg/dL, though targets may be lower (<70 mg/dL) for high-risk patients based on individual cardiovascular risk assessment.

Q5: Can this equation be used for children?
A: While the equation can be applied, pediatric lipid values and interpretations differ from adults, and age-specific percentiles should be used for assessment.