Coronary calcium score test: What it is and what your score means

A coronary artery calcium (CAC) score — sometimes called a calcium scan, heart scan, or Agatston score — is a quick CT scan that detects calcified plaque in the walls of your heart's arteries. The result helps clinicians estimate your near-term risk for heart attack or stroke and guides decisions about preventive treatment like statins, blood pressure medications, and lifestyle changes.¹

What is a coronary calcium score?

The CAC test uses a non-contrast CT scan to identify calcium in the coronary arteries that supply blood to your heart. Calcium in artery walls is a marker of underlying atherosclerosis (plaque buildup), which over time can narrow vessels or rupture and cause a heart attack. The Agatston score combines the area and density of calcium across all your coronary arteries into a single number.²

How is the test done?

You lie on a table that slides through a doughnut-shaped CT scanner. Electrodes monitor your heart rhythm so the scan can capture images between heartbeats. The whole procedure takes 10 to 15 minutes, requires no IV contrast, and exposes you to a low dose of radiation, often comparable to a mammogram. There is no special preparation other than avoiding caffeine for a few hours, which can raise your heart rate and blur images.³

What do the score numbers mean?

Agatston scores are typically interpreted as follows: a score of 0 indicates no detectable calcified plaque and very low short-term cardiovascular risk; 1 to 99 suggests mild plaque; 100 to 299 indicates moderate plaque; and 300 or higher reflects extensive plaque and high cardiovascular risk.⁴ Reports often also list a percentile based on your age, sex, and race so you can see how your score compares with peers.

Who should consider a calcium score?

The 2017 SCCT consensus and subsequent guidelines support CAC testing for asymptomatic adults aged 40 to 75 with a 10-year ASCVD risk between 5 percent and 20 percent, and for adults with under 5 percent risk who have a strong family history of premature coronary artery disease.⁵ CAC is generally not recommended for low-risk adults under 40, people who already have known coronary disease, or people with very high risk where treatment is already indicated.

How does the score change treatment decisions?

A CAC of 0 in an intermediate-risk adult often supports deferring or de-escalating preventive medications because the risk of a heart attack in the next decade is very low. A CAC of 100 or more, especially with risk factors like high LDL cholesterol, hypertension, smoking, or family history, generally supports starting or intensifying statin therapy and aggressive lifestyle changes. Your clinician will weigh your CAC alongside cholesterol panels, blood pressure, and other risk factors to make a personalized plan.⁶

Are there limits to the test?

CAC scoring detects calcified plaque but cannot identify soft (non-calcified) plaque, which is more common in younger adults and people with diabetes. A score of 0 lowers but does not eliminate cardiovascular risk, especially if you smoke or have other strong risk factors. The test is not a diagnostic tool for active chest pain — if you have symptoms, talk to your clinician about whether a stress test, CT angiography, or emergency evaluation is more appropriate.¹

Will insurance cover a calcium score?

Coverage varies. Some insurers and Medicare cover calcium scoring for selected patients with risk factors; many treat it as a screening test and ask patients to pay out of pocket, often $50 to $200. Confirm pricing and coverage with the imaging center and your plan before scheduling.

Next steps

If you and your clinician are weighing whether to start a statin or want a clearer picture of your heart attack risk, a calcium score can help. Solv can help you find local imaging centers and same-day urgent care visits to discuss your results and any follow-up testing.