Updated
What the scan measures
A coronary artery calcium (CAC) scan is a noncontrast CT scan that measures calcified plaque in the heart arteries. It uses a small amount of radiation. The result is usually reported as an Agatston score, sometimes with a percentile for people of similar age and sex.
A calcium score does not measure the percentage of narrowing in an artery. It also does not show all noncalcified plaque.
Making sense of your result
| Score | What it tells us |
|---|---|
| 0 | No calcified plaque detected. Often reassuring for near-term risk, but it does not exclude all plaque or explain away symptoms. |
| 1-99 | Calcified plaque is present. Discuss prevention in the context of your age and other risk factors. |
| 100-299 | A larger plaque burden that strengthens the case for intensive risk-factor management. |
| 300 or higher | A substantial plaque burden. Make a clear prevention and follow-up plan with your clinician. |
What might change afterward?
The result may help settle an uncertain decision about cholesterol-lowering treatment. Current guidance uses overall cardiovascular risk and the amount of calcium to inform LDL goals. A zero score does not automatically remove the need for treatment, especially with conditions such as diabetes, very high LDL or a strong family history.
Do not start aspirin because of the score alone. Its possible benefit must be weighed against bleeding risk, age and overall cardiovascular risk. If aspirin is already prescribed, discuss changes with the prescriber.
Who needs a different test?
CAC is mainly a prevention tool for selected people without symptoms. Chest symptoms may require a different assessment, such as a stress test or coronary CTA, depending on the situation.
Repeating CAC is not a routine way to measure whether a statin is working. Your clinician can explain whether another scan would change care. Ask the imaging center about cost and coverage before scheduling.
When symptoms change the plan
New severe chest discomfort, trouble breathing, fainting or stroke symptoms warrant emergency evaluation. Call 911; do not wait for a screening scan or a routine results visit. Discuss new, less urgent symptoms with your clinician even if your calcium score was zero.
Questions for your next visit
- How does my score change my prevention plan?
- What cholesterol goal is right for me?
- Would another test change what we do?
References and further reading
- ACR/RSNA RadiologyInfo: Cardiac CT for Calcium Scoring
- ACC/AHA: 2026 Guideline on the Management of Dyslipidemia
- ACC: Aspirin for primary prevention and bleeding risk (2022)
- ACC: Coronary calcium and estimated net benefit of aspirin (2020)
Use these sources with your own clinician's advice. Recommendations depend on your health history and can change as evidence develops.