Heart Disease Health Center

Risks

The chance of a coronary calcium scan causing a problem is small.

• There is a slight chance of developing cancer from having a coronary calcium scan. The chance is higher in people who have many radiation tests. If you are concerned about this risk, talk to your doctor about the amount of radiation this test may give you and confirm that the test is needed.
• There is a slight risk that a CT scan can interfere with implanted or external medical devices. Examples of medical devices include pacemakers, insulin pumps, defibrillators, and neurostimulators.
• You could get a high score from the test even if your arteries are not blocked. This could lead to extra tests that you don't need. Or it could cause you to worry when there’s no reason. But these kinds of results are most likely to happen in people who are at low risk for heart disease. So if you already know that you're at low risk, you shouldn't get this test.
• Not all blocked arteries have calcium. A low test score may make you feel safe even though you're still at risk.

Results

After you have the test, talk with your doctor about your results. The radiologist may discuss initial results with you right after the test.

Your test result is a number that is your calcium score. The score can range from 0 to more than 400. Any score over 100 means that you are likely to have heart disease. The higher your score, the greater your chance of having a heart attack.

People who score between 100 and 400 or higher, and who are at medium risk for heart disease, are more likely to have a heart attack in the next 3 to 5 years than people who score 0.²

What Affects the Test

Reasons you may not be able to have the test or why the results may not be helpful include:

• Having a fast heart rate.
• Smoking.
• Caffeine use.

What To Think About

• Plaque that is not hard (soft plaque) can't be found with a coronary calcium scan. Soft plaque is the earliest form of damage to the arteries of the heart. If you have soft plaque in your arteries, the test may give normal results, but this is a false-negative result. The buildup of soft plaque can also cause a heart attack.
• Coronary calcium scans are not needed very often because a physical exam and other tests can give information about your heart. This test is not advised for routine screening for coronary artery disease.¹
• If your coronary calcium scan shows that you have a high chance of having heart disease, you can take steps to lower your chance. Eat better, quit smoking, and get more exercise. These are the same steps your doctor would recommend after looking at your health history, your physical health, and any lab tests, such as a cholesterol test. If you have high blood pressure or high cholesterol, talk to your doctor about your treatment choices.
• It is possible to have false-positive test results. This means that the test shows a high chance of blockage in the arteries of the heart when it is not true. People with a low chance of heart disease are most likely to have a false-positive test.
• Coronary calcium scans may not be covered by all health insurance plans.
• Coronary calcium scans may not be available in some areas of the United States, such as in small towns.
• Sometimes doctors automatically schedule routine tests because they think that's what patients expect. But experts say that routine heart tests can be a waste of time and money. For information, see Heart Tests: When Do You Need Them?