LDL Calculator in mmol/L

Friedewald Equation:

\[ LDL-C = TC - HDL-C - \frac{TG}{2.2} \]

LDL Cholesterol (LDL-C):

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1. What is the Friedewald Equation?

The Friedewald equation is a formula used to estimate LDL cholesterol (LDL-C) 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:

\[ LDL-C = TC - HDL-C - \frac{TG}{2.2} \]

Where:

\( LDL-C \) — Low-density lipoprotein cholesterol (mmol/L)
\( TC \) — Total cholesterol (mmol/L)
\( HDL-C \) — High-density lipoprotein cholesterol (mmol/L)
\( TG \) — Triglycerides (mmol/L)

Explanation: The equation estimates LDL cholesterol by subtracting HDL cholesterol and VLDL cholesterol (estimated as TG/2.2) 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 lipid-lowering therapy decisions.

4. Using the Calculator

Tips: Enter total cholesterol, HDL cholesterol, and triglycerides in mmol/L. All values must be valid (positive numbers). Note: This equation is not valid when triglycerides exceed 4.5 mmol/L.

5. Frequently Asked Questions (FAQ)

Q1: When is the Friedewald equation not accurate?
A: The equation becomes inaccurate when triglycerides exceed 4.5 mmol/L, in non-fasting samples, or in patients with dysbetalipoproteinemia.

Q2: What are the limitations of this calculation?
A: It assumes a fixed ratio of triglycerides to VLDL cholesterol (5:1 in mg/dL or 2.2:1 in mmol/L), which may not hold true in all individuals.

Q3: When should direct LDL measurement be used instead?
A: Direct measurement is preferred when triglycerides are >4.5 mmol/L, in non-fasting states, or when precise LDL quantification is clinically necessary.

Q4: What are optimal LDL-C levels?
A: Generally, <2.6 mmol/L for high-risk patients and <3.4 mmol/L for moderate-risk individuals, though targets vary based on specific guidelines and patient factors.

Q5: Can this calculator be used for children?
A: The equation is primarily validated for adults. Pediatric lipid assessment should follow age-specific guidelines and may require specialized approaches.