1. What is the Friedewald Equation?

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

2. How Does the Calculator Work?

The calculator uses the Friedewald equation adapted for mmol/L:

Where:

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

Explanation: The equation 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 assess cardiovascular risk and guide treatment decisions, particularly for cholesterol-lowering therapies.

4. Using the Calculator

Tips: Enter total cholesterol, HDL cholesterol, and triglycerides in mmol/L. All values must be valid (greater than 0). For accurate results, measurements should be taken from a fasting blood sample.

5. Frequently Asked Questions (FAQ)

Q1: When is the Friedewald equation not accurate?
A: The equation is less accurate when triglyceride levels are above 4.5 mmol/L, in non-fasting samples, or in patients with certain metabolic disorders.

Q2: What are optimal LDL cholesterol levels?
A: Generally, LDL below 2.6 mmol/L is optimal for most adults, but targets may be lower for high-risk individuals (below 1.8 mmol/L).

Q3: How often should cholesterol be measured?
A: Adults should have cholesterol checked every 4-6 years, or more frequently if risk factors exist or treatment is ongoing.

Q4: Are there alternatives to the Friedewald equation?
A: Yes, direct LDL measurement or the Martin/Hopkins equation may be used when triglycerides are elevated or for greater accuracy.

Q5: Why is fasting important for accurate results?
A: Fasting (9-12 hours) provides more stable triglyceride levels, which improves the accuracy of the calculated LDL value.