Friedewald Equation:
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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.
The calculator uses the Friedewald equation:
Where:
Explanation: The equation estimates LDL cholesterol by subtracting HDL cholesterol and VLDL cholesterol (estimated as TG/2.2) from total cholesterol.
Details: LDL cholesterol is a major risk factor for cardiovascular disease. Accurate estimation helps assess cardiovascular risk and guide treatment decisions, particularly regarding lipid-lowering therapy.
Tips: Enter all values in mmol/L. All values must be valid (greater than 0). Note: This equation is less accurate when triglyceride levels exceed 4.5 mmol/L.
Q1: When is the Friedewald equation not accurate?
A: The equation becomes less reliable when triglyceride levels exceed 4.5 mmol/L, in non-fasting samples, or in patients with certain metabolic disorders.
Q2: What are optimal LDL cholesterol levels?
A: Generally, LDL-C below 2.6 mmol/L is optimal for most adults, and below 1.8 mmol/L for high-risk patients, though targets may vary based on individual risk factors.
Q3: Should I be fasting for this test?
A: Yes, lipid profiles including triglycerides should be measured after a 9-12 hour fast for most accurate results.
Q4: Are there alternatives to the Friedewald equation?
A: Yes, direct LDL measurement or the Martin/Hopkins method may be used, especially when triglyceride levels are elevated.
Q5: How often should LDL be checked?
A: Frequency depends on individual risk factors, but generally every 4-6 years for adults with normal levels, and more frequently for those with elevated levels or on treatment.