Non-HDL-C represents the level of cholesterol in the blood that is not considered “good cholesterol” and that contributes to the risk of developing cardiovascular disease (CVD). The non-HDL-C fraction is now considered more indicative than the LDL cholesterol fraction for assessing the risk of CVD because it includes all fractions that may contribute to the formation of cholesterol plaques in the blood vessels (LDL cholesterol, VLDL, etc.). Also, the measurement of the non-HDL-C fraction is not affected by food intake.
Non-HDL-C levels are interpreted in light of the risk of developing CVD within 10 years following the test (Framingham risk), a calculation that factors in age, sex, smoking, treated or untreated hypertension, and the presence of diabetes in addition to HDL cholesterol and total cholesterol levels. The higher the Framingham risk, the lower the desirable non-HDL-C level should be. The Canadian Cardiovascular Society recommends lowering non-HDL cholesterol levels to under 2.6 millimoles per litre (mmol/L) in all individuals with a Framingham risk above 20% (high risk) and in individuals with a risk between 10% and 20% (intermediate risk) as soon as their non-HDL-C levels exceed 4.3 mmol/L.