Cholesterol ratio guidelines are important because ratios can be an indicator of a person's risk for heart disease. Based on guidelines provided by the American Heart Association (AHA), people should aim for a cholesterol ratio that is at or below 5 to 1, states Mayo Clinic. The cholesterol ratio is calculated by dividing the total cholesterol number by the high-density lipoprotein (HDL) cholesterol number.
HDL cholesterol is usually referred to as "good cholesterol" whereas low-density lipoprotein (LDL) cholesterol is termed "bad cholesterol." Another component associated with cholesterol is very low-density lipoprotein (VLDL). The total cholesterol number is a combination of the LDL, HDL and VLDL components. it is a measure of how much fat is in the blood.
The ratio can assist doctors monitor a patient for heart disease risks; however, the AHA specifies that the total cholesterol number should be used by doctors to treat patients instead of cholesterol ratios, states WebMD. The reason for this is that total cholesterol numbers are better indicators of a cholesterol problem. Knowing the cholesterol levels of all components can also help doctors provide the proper treatment options to correct the condition.
When the total cholesterol number is very high, it can place a person at a higher risk for a stroke and heart attack, according to WebMD. This is because cholesterol can cause plaque formation in arteries that may lead a blockage. Blockage also can cause angina.