LDL Calculated Test

Friedewald Formula:

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

Calculated LDL (LDL-C):

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1. What Is LDL Calculated Test?

The LDL calculated test uses the Friedewald formula to estimate low-density lipoprotein (LDL) cholesterol levels from total cholesterol, HDL cholesterol, and triglyceride measurements. It provides a cost-effective alternative to direct LDL measurement for assessing cardiovascular risk.

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: Accurate LDL estimation is crucial for assessing cardiovascular risk, guiding lipid-lowering therapy, and monitoring treatment effectiveness in managing 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 accurate when triglycerides exceed 400 mg/dL.

5. Frequently Asked Questions (FAQ)

Q1: Why use calculated LDL instead of direct measurement?
A: Calculated LDL is more cost-effective and widely available, though direct measurement may be preferred when triglycerides are very high (>400 mg/dL).

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

Q3: When should lipid testing be performed?
A: Fasting for 9-12 hours is recommended for accurate triglyceride measurement, which affects LDL calculation.

Q4: Are there limitations to the Friedewald formula?
A: Less accurate when triglycerides >400 mg/dL, in non-fasting samples, or with very low LDL levels.

Q5: Are there alternative calculation methods?
A: Yes, the Martin/Hopkins method and other equations may provide better accuracy in certain populations.