1. What is the LDL Calculation?

The Friedewald formula estimates LDL cholesterol from total cholesterol, HDL cholesterol, and triglycerides. It's commonly used when direct LDL measurement isn't available and provides a reliable estimate in most cases.

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)

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 valid when triglycerides are below 400 mg/dL. For higher TG levels, direct LDL measurement is recommended.

5. Frequently Asked Questions (FAQ)

Q1: When is this calculation not accurate?
A: When triglycerides are >400 mg/dL, in non-fasting samples, or in patients with type III hyperlipoproteinemia.

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: Should this be used for children?
A: The formula can be used for children, but pediatric reference ranges differ by age and sex.

Q4: How does fasting affect the calculation?
A: Non-fasting samples may have elevated triglycerides, making the LDL estimate less accurate.

Q5: Are there alternative calculation methods?
A: Yes, the Martin/Hopkins method adjusts the TG/VLDL ratio based on triglyceride and non-HDL cholesterol levels.