The cholesterol to high-density lipoprotein (HDL) ratio, is commonly written as TC/HDL-C.
It is calculated by dividing total cholesterol by HDL cholesterol.
This ratio is widely used as a marker of cardiovascular risk, with higher values indicating greater risk for coronary heart disease (CHD) and other adverse outcomes.
The TC/HDL-C ratio integrates the atherogenic potential of total cholesterol and the protective effect of HDL cholesterol.
A ratio above 4.5 is generally considered elevated and associated with increased CHD risk.
Lower ratios are more favorable for risk.
TC/HDL-C ratio ≥4.5 identifies individuals at higher risk for CHD.
Ratios above 5 have been associated with a twofold or greater increase in CHD risk, independent of LDL cholesterol levels.
The TC/HDL-C ratio is a more powerful predictor of cardiovascular events than total cholesterol or LDL cholesterol alone, and is useful for risk stratification and guiding lipid-lowering therapy.
It can help identify patients who may benefit from more intensive lipid modification, especially when LDL cholesterol levels are not markedly elevated but the ratio is high.