🫀 LDL Cholesterol (Friedewald)
Calculate LDL cholesterol from a lipid panel with the Friedewald equation.
Clinical takeaway
Underestimates LDL at low LDL or high triglycerides.
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When to use
Estimate LDL when a direct measurement is unavailable.
How it works
LDL = TC − HDL − TG/5 (mg/dL); invalid at triglycerides ≥ 400 mg/dL.
Key points
- Underestimates LDL at low LDL or high triglycerides.
- Use direct LDL or Martin-Hopkins when more accuracy is needed.
- Requires a fasting sample for best accuracy.
References
Decision support for licensed clinicians only; not a substitute for clinical judgement, diagnosis or local protocols.
Worked calculation
The values below come from this tool's own example placeholders and are computed server-side with the formula shown on this page, so the arithmetic can be checked quickly. It demonstrates how to substitute values only — it is not clinical advice and not a real case.
| Total cholesterol | 200 mg/dL |
|---|---|
| HDL cholesterol | 50 mg/dL |
| Triglycerides | 150 mg/dL |
→Calculated LDL120mg/dL
- Formula：LDL = TC − HDL − TG/5 (mg/dL)
- Caution：Underestimates LDL at low LDL or high TG; invalid if TG ≥ 400.
Frequently asked questions
- What is LDL Cholesterol (Friedewald)?
- Calculate LDL cholesterol from a lipid panel with the Friedewald equation.
- How is LDL Cholesterol (Friedewald) calculated? What is the core formula?
- LDL = TC − HDL − TG/5 (mg/dL); invalid at triglycerides ≥ 400 mg/dL.
- When is LDL Cholesterol (Friedewald) used?
- Estimate LDL when a direct measurement is unavailable.
- What are the key clinical points for LDL Cholesterol (Friedewald)?
- Underestimates LDL at low LDL or high triglycerides. Use direct LDL or Martin-Hopkins when more accuracy is needed. Requires a fasting sample for best accuracy.
- What are the limits and cautions when using LDL Cholesterol (Friedewald)?
- For licensed clinicians and clinical researchers. Interpret results with history, investigations and local protocols; not a diagnosis or prescription, and not a substitute for multidisciplinary decision-making or local guidelines.
- How is LDL Cholesterol (Friedewald) calculated in practice? Can you show a worked example?
- Inputs: Total cholesterol 200 mg/dL, HDL cholesterol 50 mg/dL, Triglycerides 150 mg/dL → Result: Calculated LDL 120 mg/dL（Formula: LDL = TC − HDL − TG/5 (mg/dL), Caution: Underestimates LDL at low LDL or high TG; invalid if TG ≥ 400.）