The Cardiovascular
ToolsCalculators

LDL cholesterol — Friedewald equation

Calculated LDL cholesterol from the standard lipid panel.

LDL cholesterol — Friedewald equation
Total cholesterol
HDL cholesterol
Triglycerides
Complete the fields above to see the result.

When to use

  • Routine estimation of LDL cholesterol when a direct assay is unavailable and triglycerides are <400 mg/dL (<4.5 mmol/L).

Formula

LDL = total cholesterol − HDL − (triglycerides / 5) in mg/dL, which is triglycerides / 2.2 when working in mmol/L.

Pearls and pitfalls

  • Underestimates LDL at low LDL levels and at high triglycerides — precisely the patients in whom accuracy matters most.
  • Non-HDL cholesterol is unaffected by triglycerides and is a useful alternative target in hypertriglyceridaemia.

References

  1. Friedewald WT, Levy RI, Fredrickson DS. Estimation of the concentration of low-density lipoprotein cholesterol in plasma, without use of the preparative ultracentrifuge. Clin Chem. 1972;18(6):499–502.