Martin LDL Calculator

The Martin equation (also called the Hopkins method) estimates LDL cholesterol (LDL-C) from a standard lipid panel. It improves on the Friedewald equation by replacing the fixed triglyceride ÷ 5 factor with a novel factor that varies with triglycerides and non-HDL cholesterol.

This approach was compared with Friedewald in Martin et al., JAMA 2013;310(19):2061-8.

Equations

Non-HDL cholesterol = Total cholesterol - HDL cholesterol

LDL cholesterol = Non-HDL cholesterol - (Triglycerides / Novel factor)

The novel factor represents the triglyceride to VLDL-cholesterol ratio. It is looked up from a table indexed by triglyceride level (mg/dL) and non-HDL cholesterol (mg/dL).

Novel factor table

Columns are non-HDL cholesterol strata (mg/dL). Rows are triglyceride strata (mg/dL).

Units

• Total cholesterol and HDL: mg/dL or mmol/L (conversion factor 38.66976 for mmol/L to mg/dL).
• Triglycerides: mg/dL (required for the novel factor table).

Notes

• The novel factor improves LDL estimation across a wide range of triglyceride levels, including ranges where Friedewald is less reliable.
• This calculator does not replace clinical judgment or laboratory measurement when a direct LDL assay is indicated.
• Discuss your lipid results with your healthcare provider.

1. Enter total cholesterol and choose mg/dL or mmol/L next to the field.
2. Enter HDL cholesterol and choose its unit.
3. Enter triglycerides in mg/dL.
4. Tap Calculate to see LDL cholesterol, non-HDL cholesterol, and the novel factor used.

Minimum values are 0. Triglycerides above 13975 mg/dL are outside the table range used by this method.