Friedewald Formula For LDL Calculation

Friedewald Formula:

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

LDL Cholesterol (LDL-C):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is the Friedewald Formula?

The Friedewald formula is a widely used equation for estimating LDL cholesterol levels from standard lipid panel measurements. It provides a calculated LDL value without requiring direct measurement, making it a cost-effective alternative in clinical practice.

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 patients with 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 valid when triglycerides exceed 400 mg/dL.

5. Frequently Asked Questions (FAQ)

Q1: When should the Friedewald formula not be used?
A: The formula should not be used when triglyceride levels exceed 400 mg/dL, as it becomes less accurate in these cases.

Q2: What are the limitations of the Friedewald formula?
A: It may underestimate LDL levels in patients with very low LDL cholesterol or diabetes, and overestimate in those with hypertriglyceridemia.

Q3: Are there alternative methods for LDL calculation?
A: Yes, direct LDL measurement or the Martin/Hopkins method can be used, especially when triglycerides are elevated.

Q4: What are optimal LDL levels?
A: Generally, LDL below 100 mg/dL is optimal, below 70 mg/dL for high-risk patients, and below 55 mg/dL for very high-risk patients.

Q5: Should fasting samples be used?
A: Yes, for accurate results, blood samples should be collected after a 9-12 hour fast to minimize triglyceride variability.