1. What is the Friedewald Equation?

The Friedewald equation estimates LDL cholesterol (LDL-C) from total cholesterol, HDL cholesterol, and triglyceride levels. It provides a practical method for LDL-C estimation without requiring direct measurement.

2. How Does the Calculator Work?

The calculator uses the Friedewald equation:

Where:

• \( TC \) — Total cholesterol (mg/dL)
• \( HDL\text{-}C \) — HDL cholesterol (mg/dL)
• \( TG \) — Triglycerides (mg/dL)

Explanation: The equation estimates LDL-C by subtracting HDL-C and VLDL-C (estimated as TG/5) from total cholesterol.

3. Importance of LDL-C Calculation

Details: LDL cholesterol is a major risk factor for cardiovascular disease. Accurate estimation helps in assessing cardiovascular risk and guiding lipid-lowering therapy.

4. Using the Calculator

Tips: Enter total cholesterol, HDL cholesterol, and triglycerides in mg/dL. All values must be valid (greater than 0). The equation is not valid when triglycerides exceed 400 mg/dL.

5. Frequently Asked Questions (FAQ)

Q1: When is the Friedewald equation not accurate?
A: The equation is less accurate when triglycerides are above 400 mg/dL, in non-fasting samples, or in certain metabolic disorders.

Q2: What are optimal LDL-C levels?
A: Optimal LDL-C is generally below 100 mg/dL, though targets may vary based on individual cardiovascular risk factors.

Q3: How should blood samples be collected?
A: Fasting samples (9-12 hours) are preferred for accurate triglyceride measurement, which affects LDL-C calculation.

Q4: Are there alternatives to the Friedewald equation?
A: Yes, direct LDL-C measurement or other equations like Martin-Hopkins may be used, especially when triglycerides are elevated.

Q5: Can this calculator be used for children?
A: The equation is primarily validated for adults. Pediatric LDL-C assessment may require different approaches.