What You Need to Know About Coronary Calcium Scans

Updated July 2026

Sometimes, deciding whether someone should be on statins (medications like atorvastatin and rosuvastatin) is very clear. If a patient has documented heart disease, diabetes, or a genetically driven very high cholesterol number, placing them on a statin makes a lot of sense. Not because statins make cholesterol numbers look better, but because under those circumstances statins have been shown over and over again to reduce the risk of subsequent heart events.

But many people without known heart disease, diabetes or genetically driven very high cholesterol numbers are advised to take cholesterol lowering drugs. If that describes you, you might just benefit from a coronary calcium scan to determine if you really need those medications.

Here are a few things you should know before you talk to your doctor about getting this type of evaluation:

What is a coronary calcium scan?

A coronary calcium scan is a CT scan of your heart. It does not involve any dye injections and radiation exposure is minimal. During the scan, around 50 parallel slices of your chest are obtained by the CT scanner, enabling us to "see" whether calcium is building up in your heart arteries. While calcium itself is not dangerous, it likes to hang out with plaque deposits. And plaque is bad news for your heart.

Doctors scan for calcium deposits in heart arteries because they're really easy to detect with a CT scan (they look bright white, while the heart itself looks grey), and because calcium usually starts to accumulate way before significant blockages develop. So, coronary calcium scans are great for detecting coronary artery disease very early, way before a stress test would signal a problem.

When you have a coronary calcium test, a computer program analyzes the images obtained during the scan and comes up with a "calcium score". The more calcium has deposited in your arteries, the higher your score. As we get older, the chance that some calcium is detected goes up, and based upon hundreds of thousands of patients who have had this test done, we know what score to expect given your age and sex.

Why does calcium deposit in arteries in the first place?

When plaque develops, it doesn't accumulate in your arteries evenly. Rather it accumulates in lumps and bumps. That's why someone can have a 90% blockage that can be fixed with one small stent. That 90% obstruction does not involve the whole heart artery, just one localized spot.

When lumps and bumps develop in your artery walls, they distort the underlying artery wall architecture, creating weak points. The body recognizes these areas of vulnerability and tries to reinforce them by building permanent scaffolding. That scaffolding is made out of calcium.

Scaffolding makes the plaque deposits more sturdy, less likely to break down and cause out of the blue events like heart attacks and strokes. So calcified plaque is "stable" plaque. It's the body's attempt to heal itself.

But we know that wherever there is calcified plaque, there is also uncalcified, less stable plaque. So, the calcium deposits are not the real problem. They're just the marker of the problem. And, typically, the more calcified plaque there is, the more uncalcified plaque is present. Our prevention efforts are actually all aimed at uncalcified plaque, which can be significantly diminished with intensive prevention efforts.

What does a calcium score of zero mean?

Back to the calcium score. It's probably the only time in your life you want to be a zero. A zero score means that no calcified plaque was identified and (based upon multiple studies) that your risk of having a heart attack, or needing a stent or bypass surgery, is extremely low, now and for the next few years. So low, in fact, that putting you on a statin would be unlikely to make that risk any lower, even if the drug made your cholesterol numbers look better.

This low risk "guarantee" does not last forever – about 3 to 5 years. So it's still important to attend to any risk factors you have and consider repeat testing in 3 to 5 years to confirm you are staying in the low-risk group. A 0 score is also not a reason to throw common sense out the window. If you start experiencing new symptoms (like chest pain or unusual shortness of breath) we should still investigate them.

Recently, a large analysis published in the Journal of the American College of Cardiology showed that calcium scores under 10 are also associated with very low risk in men over age 55 and women over age 60. So, another group that could potentially avoid statin drugs, at least for a few years.

What if your score is not zero, especially if it is over 10?

First, do not panic. Any calcium that is detected did not build up overnight. It takes years for calcium to deposit, so think of it more as a report card on your heart's health up until now.

Second, remember that calcium becomes more common as we get older. So the score still has to be put in context of your age and sex.

Finally, look at this as an opportunity to change the trajectory of a health issue that was silently lurking within. Remember, uncalcified plaque can be reversed. To accomplish this may mean taking statins for lowering your cholesterol as well as being very aggressive in addressing any other risk factors that you have. In some individuals, a high score indicates that additional lab testing makes sense, to evaluate lipoprotein A and apolipoprotein B levels, for example. Your doctor may also recommend a stress test, especially if your score is over 400.

The highest score I've ever seen in a patient where I've ordered the test? 2,217. I've seen reports of scores over 6,000.

But even at 2,217 an abnormal coronary calcium report is NOT an emergency. Again, calcium does not build up overnight. Your non-zero calcium score would have been very similar six months or even a year ago. More than anything, the calcium score provides a very useful benchmark to evaluate your personal heart disease risk.

A few practical things to know

Calcium supplements do not cause coronary calcium; the calcium in your blood has nothing to do with the calcium in your artery walls. The scan is also not an angiogram, it measures calcium rather than the degree of narrowing, so it cannot tell you whether a significant blockage is present. That is what a stress test is for.

Arterial calcium does not disappear, so once it is found, especially if it is higher than expected for your age and sex, there is no reason to repeat the scan; with a zero or very low score, every three to five years is plenty. Some people do not need the test at all. If you have already had a heart attack, stent, or bypass, or you have diabetes or familial hypercholesterolemia, we already know you are high risk and should be treated aggressively.

Because the scan is considered preventive, insurance may not always cover it, though a physician referral improves your chances; out of pocket it runs around $150. You can refer yourself for the test, but I would not recommend going it alone, because a calcium score is only one piece of your risk picture and you will want a clinician to help you interpret it. And to reiterate, a low or zero score is never a free pass to coast. Keep exercising, stay smoke-free, and eat well.

What matters most, whatever your score?

Whether a patient comes to me with a score of zero or one in the thousands, my first recommendation is the same: eat a healthy diet, because food has such profound effects on the heart and vascular system. I started Step One Foods to make healthy eating easier for my patients, packing each serving with as much whole-food fiber, plant sterols, and omega-3 fatty acids as possible, because those are the nutrients that help keep your arteries as clean as possible.

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