1. What is the Rearranged Friedewald Equation?

The rearranged Friedewald equation estimates HDL cholesterol from total cholesterol, LDL cholesterol, and triglycerides. This is a rearrangement of the original Friedewald formula used to estimate LDL cholesterol.

2. How Does the Calculator Work?

The calculator uses the rearranged Friedewald equation:

Where:

• \( HDL \) — HDL cholesterol (mg/dL)
• \( TC \) — Total cholesterol (mg/dL)
• \( LDL \) — LDL cholesterol (mg/dL)
• \( TG \) — Triglycerides (mg/dL)

Explanation: This equation rearranges the original Friedewald formula to solve for HDL instead of LDL, using the standard approximation that VLDL cholesterol equals triglycerides divided by 5.

3. Importance of HDL Calculation

Details: HDL cholesterol is known as "good cholesterol" as it helps remove other forms of cholesterol from the bloodstream. Higher levels of HDL are associated with reduced cardiovascular risk.

4. Using the Calculator

Tips: Enter total cholesterol, LDL cholesterol, and triglycerides in mg/dL. All values must be valid (positive numbers). This calculation is most accurate when triglycerides are below 400 mg/dL.

5. Frequently Asked Questions (FAQ)

Q1: Why use this rearranged equation instead of direct HDL measurement?
A: Direct HDL measurement is preferred, but this calculation can be useful when only total cholesterol, LDL, and triglycerides are available.

Q2: What are normal HDL values?
A: Optimal HDL levels are typically above 40 mg/dL for men and 50 mg/dL for women. Levels below these thresholds may increase cardiovascular risk.

Q3: When is this calculation not accurate?
A: This calculation becomes less accurate when triglycerides exceed 400 mg/dL, in non-fasting samples, or in certain medical conditions like dysbetalipoproteinemia.

Q4: How can I increase my HDL levels?
A: Regular exercise, maintaining a healthy weight, quitting smoking, and consuming healthy fats can help increase HDL levels.

Q5: Should this calculated HDL value be used for clinical decisions?
A: Direct laboratory measurement of HDL is always preferred for clinical decision making. This calculation should be used for informational purposes only.