1. What is the Friedewald Equation?

The Friedewald equation estimates LDL cholesterol (LDL-C) from total cholesterol (TC), HDL cholesterol (HDL-C), and triglycerides (TG). It provides a practical method for assessing LDL levels without direct measurement, though it has limitations at very high triglyceride levels.

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 and VLDL (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 treatment decisions, particularly statin therapy.

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 accurate when triglycerides exceed 400 mg/dL.

5. Frequently Asked Questions (FAQ)

Q1: What does high LDL-C mean?
A: High LDL cholesterol indicates increased risk of atherosclerosis and cardiovascular events. Levels above 160 mg/dL are considered high, and above 190 mg/dL are very high.

Q2: What are the limitations of the Friedewald equation?
A: It becomes inaccurate when triglycerides exceed 400 mg/dL, in non-fasting samples, and in certain metabolic disorders. Direct LDL measurement is preferred in these cases.

Q3: How often should cholesterol be tested?
A: Adults should have a lipid panel every 4-6 years. Those with risk factors or existing heart disease may need more frequent testing.

Q4: What factors can affect LDL levels?
A: Diet, exercise, weight, genetics, medications, and certain medical conditions can all influence LDL cholesterol levels.

Q5: How can I lower my LDL cholesterol?
A: Lifestyle modifications (diet, exercise, weight management) and medications (statins, ezetimibe, PCSK9 inhibitors) can effectively lower LDL levels.