1. What is the Friedewald Equation?

The Friedewald equation is a formula used to estimate LDL cholesterol levels without requiring direct measurement. It's widely used in clinical practice when direct LDL measurement is not available.

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 assess cardiovascular risk and guide treatment decisions.

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 required.

5. Frequently Asked Questions (FAQ)

Q1: When is the Friedewald equation not accurate?
A: It's less accurate when TG > 400 mg/dL, in non-fasting samples, or in patients with certain conditions like diabetes or hypertriglyceridemia.

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

Q3: Should I fast before testing?
A: Yes, a 9-12 hour fast is recommended for accurate lipid panel measurements, especially for triglyceride levels.

Q4: Are there newer equations than Friedewald?
A: Yes, the Martin/Hopkins equation may be more accurate in some cases, especially at very low LDL or high TG levels.

Q5: How often should LDL be checked?
A: Adults should be screened every 4-6 years. Those with risk factors may need more frequent testing as recommended by their doctor.