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:

• \( TC \) — Total cholesterol (mg/dL)
• \( HDL \) — HDL cholesterol (mg/dL)
• \( TG \) — Triglycerides (mg/dL)

Note: This formula is valid only when triglycerides are less than 400 mg/dL. For higher values, a direct LDL measurement is needed.

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. The formula requires fasting lipid panel results (9-12 hour fast) for accurate results. Triglycerides must be under 400 mg/dL.

5. Frequently Asked Questions (FAQ)

Q1: Why divide triglycerides by 5?
A: This approximates the cholesterol content in very low-density lipoproteins (VLDL), which carry most triglycerides in fasting blood.

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, very high ≥190 mg/dL.

Q3: When is this formula not accurate?
A: When triglycerides ≥400 mg/dL, in non-fasting samples, or with certain conditions like type III hyperlipoproteinemia.

Q4: Are there newer methods to estimate LDL?
A: Yes, the Martin/Hopkins method adjusts the TG:VLDL ratio dynamically, providing better accuracy at low LDL and high TG levels.

Q5: Should LDL be measured directly?
A: Direct measurement may be needed when triglycerides are very high (>400 mg/dL) or when more precise measurement is required.