1. What is the Friedewald Equation?

The Friedewald equation is a formula used to estimate LDL cholesterol levels from a standard lipid panel when direct LDL measurement is not available. It's widely used in clinical practice for cardiovascular risk assessment.

2. How Does the Calculator Work?

The calculator uses the Friedewald equation:

Where:

• \( TC \) — Total cholesterol (mg/dL)
• \( HDL \) — HDL 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 atherosclerosis and cardiovascular disease. Accurate estimation helps guide treatment decisions and monitor therapy effectiveness.

4. Using the Calculator

Tips: Enter all values in mg/dL from a fasting lipid panel. The equation is not valid when triglycerides are >400 mg/dL.

5. Frequently Asked Questions (FAQ)

Q1: Why use Friedewald equation instead of direct LDL measurement?
A: It's less expensive and correlates well with direct measurement when triglycerides are ≤400 mg/dL.

Q2: What are normal LDL values?
A: Optimal is <100 mg/dL, near optimal 100-129 mg/dL, borderline high 130-159 mg/dL, high 160-189 mg/dL, very high ≥190 mg/dL.

Q3: When is the Friedewald equation not accurate?
A: When TG >400 mg/dL, in non-fasting samples, or with certain conditions like type III hyperlipidemia.

Q4: Are there newer equations than Friedewald?
A: Yes, the Martin-Hopkins equation may be more accurate, especially at low LDL and high TG levels.

Q5: Should this be used for all patients?
A: For patients with TG >400 mg/dL or certain metabolic disorders, direct LDL measurement is recommended.