HDL and LDL are two different types of cholesterol that are measured as an index of a patient’s risk for cardiovascular disease. LDL and HDL are best thought of as cholesterol taxis. LDL is the “bad” taxi because it transports cholesterol and fat from the liver into the bloodstream, where it can clog arteries. HDL is the “good” taxi because it transports cholesterol from the blood back to the liver. As such, a low LDL-to-HDL ratio is a good thing, because it can reduce your risk of cardiovascular diseases.
Calculating cholesterol ratios provides useful information about your risks for cardiovascular disease, but not for determining the best way to reduce the risk if it’s high. For treatment purposes, it’s more important to know the actual numbers for all your types of cholesterol and triglycerides. People most at risk of cardiovascular disease are those with very low HDL levels or very high LDL levels
A blood sample is taken that will be used to determine the amount of bad cholesterol (low-density lipoprotein, or LDL), good cholesterol (high-density lipoprotein, or HDL) and other fatty substances (triglycerides) in your blood.
To calculate the ratio, HDL Cholesterol is divided by the total cholesterol number. An optimal ratio is less than 3.5-to-1. A higher ratio means a higher risk of heart disease.
LDL to HDL Ratio
Optimal – Less than 2.5
Moderate – 2.5 – 3.3
High – More than 3.3
HDL to LDL Ratio
Optimal – More than 0.4
Moderate – 0.4 – 0.3
High – Less than 0.3