LDL Cholesterol Calculator Formula

Friedewald Formula:

\[ LDL-C = TC - HDL-C - \frac{TG}{5} \]

LDL Cholesterol (LDL-C):

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1. What is the Friedewald Formula?

The Friedewald formula is a widely used equation to estimate LDL cholesterol levels without requiring direct measurement. It calculates LDL-C based on total cholesterol, HDL cholesterol, and triglyceride levels.

2. How Does the Calculator Work?

The calculator uses the Friedewald formula:

\[ LDL-C = TC - HDL-C - \frac{TG}{5} \]

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 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 total cholesterol, HDL cholesterol, and triglycerides in mg/dL. All values must be valid (greater than 0). Note: This formula is less accurate when triglyceride levels 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 certain medical conditions.

Q2: What are optimal LDL cholesterol levels?
A: Optimal LDL is generally below 100 mg/dL, though targets may vary based on individual cardiovascular risk factors.

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 avoid triglyceride elevation from recent meals.

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

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