1. What is the Friedewald Formula?

The Friedewald formula is a widely used equation to estimate LDL cholesterol levels from total cholesterol, HDL cholesterol, and triglyceride measurements. It provides a practical alternative to direct LDL measurement when resources are limited.

2. How Does the Calculator Work?

The calculator uses the Friedewald formula:

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 formula estimates LDL cholesterol by subtracting HDL cholesterol and one-fifth of triglycerides from total cholesterol.

3. Importance of LDL-C Calculation

Details: Accurate LDL cholesterol estimation is crucial for assessing cardiovascular risk, guiding lipid-lowering therapy, and monitoring treatment effectiveness in patients with dyslipidemia.

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 valid 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 exceed 400 mg/dL, in non-fasting samples, or in patients with certain metabolic disorders.

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

Q3: How should blood samples be collected for accurate results?
A: Fasting samples (9-12 hours) are preferred, especially when triglyceride levels are elevated, to ensure accurate LDL-C estimation.

Q4: Are there alternative methods for LDL measurement?
A: Yes, direct LDL measurement methods are available and recommended when triglycerides are >400 mg/dL or when more precise measurement is needed.

Q5: How often should LDL cholesterol be monitored?
A: Monitoring frequency depends on individual risk factors, but generally every 4-12 weeks when initiating therapy and every 3-12 months for maintenance.