1. What is the Friedewald Equation?

The Friedewald equation is a formula used to estimate LDL cholesterol levels from 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:

• \( LDL-C \) — 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 one-fifth of triglycerides from total cholesterol.

3. Importance of LDL Calculation

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

4. Using the Calculator

Tips: Enter all values 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 exceed 400 mg/dL, in non-fasting samples, or in patients with certain metabolic disorders.

Q2: What are optimal LDL cholesterol levels?
A: Generally, LDL levels below 100 mg/dL are considered optimal, below 70 mg/dL for high-risk patients, but targets may vary based on individual risk factors.

Q3: Are there alternatives to the Friedewald equation?
A: Yes, direct LDL measurement is available and more accurate, especially when triglycerides are elevated. Other formulas like the Martin/Hopkins method may also be used.

Q4: Should this be used for all patients?
A: The equation works best for patients with triglyceride levels below 400 mg/dL and without certain conditions like diabetes or chronic kidney disease.

Q5: How often should LDL be measured?
A: Frequency depends on individual risk factors, but generally every 4-6 years for adults with normal levels, more frequently for those with elevated levels or on treatment.