The blood can give many clues about heart health. For one, high levels of "bad" cholesterol in the blood can be a sign of higher risk of having a heart attack. And other substances in the blood can point to heart failure or the risk of getting fatty deposits, called plaques, in the arteries. This is called atherosclerosis.

It's important to remember that one blood test alone doesn't decide the risk of heart disease. The highest risk factors for heart disease are smoking, high blood pressure, high cholesterol and diabetes.

Here's a look at some of the blood tests used to diagnose and manage heart disease.