1. What is the Friedewald Equation?

The Friedewald equation is a formula used to estimate LDL cholesterol levels when direct measurement is not available. It calculates LDL based on total cholesterol, HDL cholesterol, and triglyceride levels.

2. How Does the Calculator Work?

The calculator uses the Friedewald equation:

Where:

• \( LDL \) — Low-density lipoprotein cholesterol (mg/dL)
• \( TC \) — Total cholesterol (mg/dL)
• \( HDL \) — High-density lipoprotein cholesterol (mg/dL)
• \( TG \) — Triglycerides (mg/dL)

Explanation: This equation estimates LDL cholesterol by subtracting HDL and VLDL (estimated as TG/5) from total cholesterol.

3. Importance of LDL Calculation

Details: LDL cholesterol is a major risk factor for cardiovascular disease. Accurate estimation helps in assessing cardiovascular risk and guiding treatment decisions for cholesterol management.

4. Using the Calculator

Tips: Enter total cholesterol, HDL cholesterol (must be <40 mg/dL), and triglycerides in mg/dL. All values must be valid positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: When should the Friedewald equation not be used?
A: It should not be used when triglyceride levels are above 400 mg/dL or in non-fasting samples.

Q2: What are optimal LDL levels?
A: Optimal LDL is <100 mg/dL, near optimal is 100-129 mg/dL, borderline high is 130-159 mg/dL, high is 160-189 mg/dL, and very high is ≥190 mg/dL.

Q3: Why is HDL <40 mg/dL considered low?
A: HDL levels below 40 mg/dL are associated with increased cardiovascular risk, as HDL helps remove LDL from arteries.

Q4: How accurate is the Friedewald equation?
A: It provides a reasonable estimate but may be less accurate than direct measurement, especially at very high or very low triglyceride levels.

Q5: Should fasting be required for this calculation?
A: Yes, for accurate results, blood should be drawn after a 9-12 hour fast as triglyceride levels are affected by recent food intake.