1. What is the Friedewald Formula?

The Friedewald formula is a widely used equation to estimate LDL cholesterol levels without direct measurement. It calculates LDL-C using total cholesterol, HDL cholesterol, and triglyceride values, providing a cost-effective alternative to direct LDL measurement.

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 and VLDL (estimated as TG/2.2) 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 all values in mmol/L. Ensure triglyceride levels are below 4.5 mmol/L for accurate results. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: When is the Friedewald formula not accurate?
A: The formula is less accurate when triglyceride levels exceed 4.5 mmol/L, in non-fasting samples, or in certain medical conditions.

Q2: What are optimal LDL cholesterol levels?
A: Optimal LDL levels are generally below 2.6 mmol/L, though targets may vary based on individual cardiovascular risk factors.

Q3: Why divide triglycerides by 2.2?
A: This factor estimates VLDL cholesterol, as VLDL typically carries about 45% of triglycerides by weight (1/2.2 ≈ 0.45).

Q4: Are there alternative methods for LDL calculation?
A: Yes, direct LDL measurement or the Martin-Hopkins method may be used when triglycerides are elevated.

Q5: Should this formula be used for everyone?
A: While useful for most people, direct measurement is recommended for those with very high triglycerides or certain metabolic disorders.