1. What is the Friedewald Equation?

The Friedewald equation is a formula used to estimate low-density lipoprotein (LDL) cholesterol levels based on measurements of total cholesterol, HDL cholesterol, and triglycerides. It provides a practical alternative to direct LDL measurement when resources are limited.

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 Cholesterol Calculation

Details: LDL cholesterol is often called "bad cholesterol" because high levels can lead to plaque buildup in arteries and increase risk of heart disease and stroke. Accurate estimation helps in cardiovascular risk assessment and treatment planning.

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 less accurate when triglyceride levels exceed 400 mg/dL.

5. Frequently Asked Questions (FAQ)

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

Q2: What are optimal LDL cholesterol levels?
A: Generally, LDL below 100 mg/dL is optimal, 100-129 mg/dL is near optimal, 130-159 mg/dL is borderline high, 160-189 mg/dL is high, and 190 mg/dL and above is very high.

Q3: Should I be fasting for this calculation?
A: Yes, for accurate results, lipid measurements should be taken after a 9-12 hour fast to minimize the effect of recent food intake on triglyceride levels.

Q4: Are there alternative methods to measure LDL?
A: Yes, direct LDL measurement is available and recommended when triglyceride levels are high or when more precise measurement is needed.

Q5: How often should LDL be checked?
A: Adults should have their cholesterol checked every 4-6 years. Those with risk factors for heart disease may need more frequent testing.