1. What is the LDL Cholesterol Equation?

The Friedewald equation estimates LDL cholesterol level from total cholesterol, HDL cholesterol, and triglycerides. It's commonly used when direct LDL measurement isn't 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. Monitoring LDL 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 needed.

5. Frequently Asked Questions (FAQ)

Q1: Why divide triglycerides by 5?
A: This estimates VLDL cholesterol, as VLDL carries about 1/5 of the triglyceride content in fasting samples.

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 this equation not accurate?
A: When triglycerides >400 mg/dL, in non-fasting samples, or with certain conditions like type III hyperlipidemia.

Q4: How often should LDL be checked?
A: Adults should have lipid profile checked every 4-6 years; more frequently if risk factors exist or treatment is initiated.

Q5: Are there newer equations than Friedewald?
A: Yes, the Martin/Hopkins equation may be more accurate, especially at low LDL or high TG levels.