1. What is the Friedewald Formula?

The Friedewald formula is a widely used equation to estimate LDL cholesterol levels without requiring direct measurement. It's particularly useful when a direct LDL measurement isn't available or feasible.

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. Accurate estimation helps assess cardiovascular risk and guide treatment decisions.

4. Using the Calculator

Tips: Enter all values in mg/dL. The formula is most accurate when triglycerides are below 400 mg/dL. For higher TG levels, direct LDL measurement is recommended.

5. Frequently Asked Questions (FAQ)

Q1: Why divide triglycerides by 5?
A: This estimates VLDL cholesterol, as VLDL typically 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 the Friedewald formula inaccurate?
A: When triglycerides are >400 mg/dL, in non-fasting samples, or in certain conditions like type III hyperlipoproteinemia.

Q4: Are there alternative formulas?
A: Yes, the Martin-Hopkins equation is a newer method that may be more accurate, especially at low LDL and high TG levels.

Q5: Should this be used for treatment decisions?
A: While useful for screening, treatment decisions should be based on comprehensive lipid assessment and cardiovascular risk evaluation.