1. What is LDL Cholesterol?

LDL (low-density lipoprotein) cholesterol, often called "bad" cholesterol, contributes to fatty buildups in arteries (atherosclerosis). The Friedewald formula provides an estimate of LDL cholesterol without requiring a direct measurement.

2. How Does the Calculator Work?

The calculator uses the Friedewald formula:

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 formula 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. Monitoring LDL levels helps assess cardiovascular risk and guide treatment decisions.

4. Using the Calculator

Tips: Enter all values in mg/dL from a fasting lipid panel. The formula is most accurate when triglycerides are below 400 mg/dL.

5. Frequently Asked Questions (FAQ)

Q1: Why divide triglycerides by 5?
A: This estimates VLDL cholesterol, as VLDL typically carries about 20% of triglycerides (hence 1/5).

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 formula inaccurate?
A: When triglycerides are >400 mg/dL, in non-fasting samples, or with certain genetic lipid disorders.

Q4: Are there alternatives to this calculation?
A: Direct LDL measurement is available but more expensive. The Martin/Hopkins method is a newer calculation for high TG levels.

Q5: How often should LDL be checked?
A: Adults should have a lipid panel every 4-6 years, more often if risk factors exist or treatment is initiated.