1. What is the Friedewald Formula?

The Friedewald formula is a widely used method to estimate LDL cholesterol (LDL-C) levels from measured total cholesterol, HDL cholesterol, and triglyceride levels. It provides a calculated LDL value that helps assess cardiovascular risk.

2. How Does the Calculator Work?

The calculator uses the Friedewald formula:

Where:

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

Explanation: The formula 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 stratification and guiding treatment decisions for lipid 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 formula is not accurate when triglycerides exceed 400 mg/dL.

5. Frequently Asked Questions (FAQ)

Q1: When is the Friedewald formula not accurate?
A: The formula becomes less accurate when triglyceride levels are above 400 mg/dL, in non-fasting samples, or in certain metabolic conditions.

Q2: What are the LDL cholesterol categories?
A: Optimal: <100 mg/dL; Near Optimal: 100-129 mg/dL; Borderline High: 130-159 mg/dL; High: 160-189 mg/dL; Very High: ≥190 mg/dL.

Q3: Are there alternative methods for LDL calculation?
A: Yes, direct LDL measurement or the Martin/Hopkins equation may be used, especially when triglycerides are elevated.

Q4: Should this be used for treatment decisions?
A: While useful for screening, treatment decisions should be based on comprehensive lipid profile and cardiovascular risk assessment.

Q5: How often should LDL be checked?
A: Frequency depends on individual risk factors, but generally every 4-6 years in adults, or more frequently if elevated or on treatment.