Calcification refers to a process in which calcium is deposited on the walls of the coronary arteries, forming a hard and brittle covering over plaque formations. Calcification may also occur around the heart’s four valves, narrowing the valve and leading to conditions such as calcific aortic valve stenosis.

New tests that measure the amount of calcium in plaque may help diagnose heart disease and the risk for stroke, even when a patient shows no outward symptoms. These new tests are noninvasive, relatively inexpensive and take only about 15 minutes. However, it's important to note there are serious limitations to these new tests, especially the use of computed tomography (CT) scanning to develop a coronary artery calcification (CAC) score.

These tests are frequently marketed to the general public by alternative health care practitioners as a method to diagnose early coronary artery disease, before symptoms become clinically apparent (e.g., asymptomatic coronary artery disease). While the CAC can yield important information, especially when combined with other measures of cardiac risk, in general, an elevated CAC alone is not enough to justify drug therapy or further invasive testing in the absence of other signs and symptoms of heart disease. Studies have yet to show any different outcomes

An elevated calcium score may be a helpful indicator that other testing is necessary, but most physicians do not rely solely on these tests for diagnosis. The nuclear stress test and cardiac catheterization (which includes a coronary angiogram) remain the gold standards for assessing the presence and severity of heart disease.