1. What is the Friedewald Equation?

The Friedewald equation estimates LDL cholesterol levels from total cholesterol, HDL cholesterol, and triglyceride measurements. It provides a practical method for assessing cardiovascular risk when direct LDL measurement is not available.

2. How Does the Calculator Work?

The calculator uses the Friedewald equation:

Where:

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

Explanation: The equation estimates LDL cholesterol by subtracting HDL cholesterol and one-fifth of triglycerides from total cholesterol.

3. Importance of LDL-C Calculation

Details: LDL cholesterol is a major risk factor for cardiovascular disease. Accurate estimation helps in risk assessment and guiding treatment decisions for cholesterol management.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: When should the Friedewald equation not be used?
A: The equation should not be used when triglyceride levels exceed 400 mg/dL, as it becomes less accurate in these cases.

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

Q3: How does this compare to direct LDL measurement?
A: Direct measurement is more accurate, especially when triglycerides are elevated, but the Friedewald equation provides a good estimate in most cases.

Q4: Should this be used for fasting or non-fasting samples?
A: The equation is typically used with fasting lipid profiles for most accurate results, though non-fasting samples may be acceptable in some contexts.

Q5: Are there limitations to this equation?
A: Besides high triglyceride limitations, the equation may be less accurate in certain populations such as those with diabetes or very low LDL levels.