1. What is the Friedewald Equation?

The Friedewald equation is a formula used to estimate LDL cholesterol (LDL-C) levels from measured values of total cholesterol, HDL cholesterol, and triglycerides. It provides a cost-effective alternative to direct LDL measurement in routine clinical practice.

2. How Does the Calculator Work?

The calculator uses the Friedewald equation:

Where:

• \( LDL-C \) — Low-density lipoprotein cholesterol (mg/dL)
• \( TC \) — Total cholesterol (mg/dL)
• \( HDL-C \) — High-density lipoprotein cholesterol (mg/dL)
• \( TG \) — Triglycerides (mg/dL)

Explanation: The equation estimates LDL cholesterol by subtracting HDL cholesterol and VLDL cholesterol (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 decisions.

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 is the Friedewald equation not accurate?
A: The equation becomes less accurate when triglycerides exceed 400 mg/dL, in non-fasting samples, or in patients with certain metabolic disorders.

Q2: What are optimal LDL-C levels?
A: Optimal LDL-C is generally below 100 mg/dL, though targets may be lower for high-risk patients (e.g., below 70 mg/dL).

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 alternative methods for LDL-C measurement?
A: Yes, direct LDL measurement methods are available and recommended when triglycerides are elevated (>400 mg/dL).

Q5: Can this equation be used for children?
A: The Friedewald equation was developed for adults and may not be accurate for pediatric populations.