1. What is the Friedewald Formula?

The Friedewald formula is a widely used method to estimate LDL cholesterol levels from total cholesterol, HDL cholesterol, and triglyceride measurements. 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 (mg/dL)
• \( TC \) — Total cholesterol (mg/dL)
• \( HDL-C \) — High-density lipoprotein cholesterol (mg/dL)
• \( TG \) — Triglycerides (mg/dL)

Explanation: The formula estimates LDL cholesterol by subtracting HDL cholesterol and one-fifth of triglycerides 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 lipid-lowering therapy decisions.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: When is the Friedewald formula not accurate?
A: The formula becomes less accurate when triglyceride levels exceed 400 mg/dL, in non-fasting samples, or in certain medical conditions like dysbetalipoproteinemia.

Q2: What are optimal LDL cholesterol levels?
A: Optimal LDL levels are generally below 100 mg/dL, though targets may vary based on individual cardiovascular risk factors.

Q3: Should samples be fasting for this calculation?
A: Yes, triglyceride levels are affected by recent food intake, so fasting samples (9-12 hours) are recommended for accurate results.

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 or when more precise measurement is needed.

Q5: Can this formula be used for children?
A: While the formula can be applied, pediatric lipid guidelines may have different interpretations and reference ranges for LDL cholesterol levels.