To calculate a patient's non-HDL cholesterol level, which fractions should be measured?

Non-HDL cholesterol is calculated by subtracting high-density lipoprotein (HDL) cholesterol from total cholesterol. This calculation is important because non-HDL cholesterol includes all atherogenic lipoproteins, which are linked to cardiovascular disease risk.

By measuring total cholesterol and HDL cholesterol, you can derive the non-HDL cholesterol using the formula:

Non-HDL cholesterol = Total cholesterol - HDL cholesterol.

This provides a comprehensive assessment of the cholesterol components that may contribute to hardening of the arteries and cardiovascular events. Other options involve the measurement of various fractions that do not directly lead to the calculation of non-HDL cholesterol, making them less appropriate for this specific question.