A total cholesterol level of more than 240 milligrams per deciliter is a high result, according to the National Heart, Lung, and Blood Institute. Experts determine cholesterol levels by measuring milligrams of cholesterol per deciliter of blood.
There are two types of cholesterol in the body: HDL and LDL cholesterol. While the total cholesterol level is a good indicator of safe levels, LDL cholesterol levels are more important to monitor. LDL cholesterol is the "bad" cholesterol that can produce blockages in the arteries. For LDL cholesterol, the optimal level is less than 100 milligrams per deciliter. One hundred sixty to 189 milligrams per deciliter is high, while 190 milligrams per deciliter and above is a very high level and increases the risk of heart disease, states the National Heart, Lung, and Blood Institute.