1. What is the Friedewald Equation?

The Friedewald equation is a formula used to estimate LDL cholesterol levels from a standard lipid panel without requiring a direct LDL measurement. It's widely used in clinical practice due to its simplicity and cost-effectiveness.

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: The equation estimates LDL 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 guide treatment decisions and assess cardiovascular risk.

4. Using the Calculator

Tips: Enter all values in mg/dL. The equation is valid only when triglycerides are below 400 mg/dL. For higher TG levels, direct LDL measurement is needed.

5. Frequently Asked Questions (FAQ)

Q1: Why use Friedewald equation instead of direct LDL measurement?
A: It's less expensive and sufficient for most clinical situations when triglycerides are <400 mg/dL.

Q2: What are normal LDL values?
A: Optimal 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: When is the Friedewald equation inaccurate?
A: When triglycerides >400 mg/dL, in non-fasting samples, or in patients with dysbetalipoproteinemia (type III hyperlipidemia).

Q4: Are there alternative equations?
A: Yes, the Martin/Hopkins equation may be more accurate for very low LDL or high TG levels.

Q5: Should this be used for all patients?
A: No, direct LDL measurement is preferred for patients with triglycerides >400 mg/dL or certain metabolic disorders.