1. What is the Friedewald Formula?

The Friedewald formula is a widely used method for estimating LDL cholesterol levels from measurements of total cholesterol, HDL cholesterol, and triglycerides. It provides a practical alternative to direct LDL measurement when resources are limited.

2. How Does the Calculator Work?

The calculator uses the Friedewald formula:

Where:

• \( LDL-C \) — Low-density lipoprotein cholesterol (mmol/L)
• \( TC \) — Total cholesterol (mmol/L)
• \( HDL-C \) — High-density lipoprotein cholesterol (mmol/L)
• \( TG \) — Triglycerides (mmol/L)

Explanation: The formula estimates LDL cholesterol by subtracting HDL cholesterol and VLDL cholesterol (estimated as TG/2.2) from total cholesterol.

3. Importance of LDL-C 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, and triglycerides in mmol/L. All values must be valid positive numbers. Note: This formula is less accurate when triglyceride levels exceed 4.5 mmol/L.

5. Frequently Asked Questions (FAQ)

Q1: Why use the Friedewald formula?
A: It provides a cost-effective and practical method for estimating LDL cholesterol when direct measurement is not available.

Q2: What are the limitations of this formula?
A: The formula is less accurate when triglyceride levels are above 4.5 mmol/L, in non-fasting samples, or in certain medical conditions.

Q3: What are optimal LDL cholesterol levels?
A: Generally, LDL-C below 2.6 mmol/L is optimal, below 3.4 mmol/L is near optimal, and above 4.1 mmol/L is high risk.

Q4: When should direct LDL measurement be used instead?
A: Direct measurement is recommended when triglycerides exceed 4.5 mmol/L or when more precise LDL assessment is needed.

Q5: Is fasting required for this calculation?
A: Yes, for accurate results, blood should be drawn after a 9-12 hour fast to ensure triglyceride levels are not artificially elevated.