1. What is LDL Cholesterol?

LDL (low-density lipoprotein) cholesterol, often called "bad cholesterol," contributes to fatty buildups in arteries (atherosclerosis). This narrows the arteries and increases risk for heart attack, stroke and peripheral artery disease.

2. How is LDL Calculated?

The calculator uses the Friedewald equation:

Where:

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

Note: This equation is valid only when triglycerides are less than 400 mg/dL. For higher values, direct LDL measurement is needed.

3. Importance of LDL Measurement

Details: LDL is a primary target of cholesterol-lowering therapy. The American Heart Association recommends:

• Optimal: <100 mg/dL
• Near optimal: 100-129 mg/dL
• Borderline high: 130-159 mg/dL
• High: 160-189 mg/dL
• Very high: ≥190 mg/dL

4. Using the Calculator

Tips: Enter all values in mg/dL from a fasting lipid panel. The calculator works best when triglycerides are below 400 mg/dL.

5. Frequently Asked Questions (FAQ)

Q1: Why calculate LDL instead of measuring it directly?
A: Calculation is cheaper and faster than direct measurement, though less accurate in some cases.

Q2: When is the Friedewald equation not accurate?
A: When triglycerides are ≥400 mg/dL, in non-fasting samples, or with certain genetic lipid disorders.

Q3: How often should LDL be checked?
A: Adults should have a lipid panel every 4-6 years. Those with risk factors may need more frequent testing.

Q4: What's the difference between LDL and non-HDL cholesterol?
A: Non-HDL cholesterol (TC minus HDL) includes all atherogenic particles and may be a better predictor of risk.

Q5: Can LDL be too low?
A: While very low LDL (<40 mg/dL) may be associated with some risks, benefits generally outweigh risks.