Heart test
Coronary Calcium Score
A coronary calcium score is a quick CT scan that measures calcium in the heart’s arteries to estimate the amount of fatty (atherosclerotic) build-up and future heart risk.
Quick answer
Coronary Calcium Score: what it is and what the results mean
A coronary artery calcium (CAC) score uses a low-dose CT scan of the heart to detect and measure calcium in the walls of the coronary arteries. Calcium is a marker of atherosclerosis, so the score reflects the burden of arterial disease.
- Why it is done: It is used to refine the estimate of future heart attack risk in people at intermediate risk, helping decide whether to start or intensify treatment such as statins, particularly when the decision is uncertain.
- Understanding results: The result is a calcium score (Agatston score): zero suggests very low risk, while higher numbers indicate more build-up and higher risk.
What it is
A coronary artery calcium (CAC) score uses a low-dose CT scan of the heart to detect and measure calcium in the walls of the coronary arteries. Calcium is a marker of atherosclerosis, so the score reflects the burden of arterial disease.
Why it is done
It is used to refine the estimate of future heart attack risk in people at intermediate risk, helping decide whether to start or intensify treatment such as statins, particularly when the decision is uncertain.
What to expect
No dye is usually needed. You lie on the scanner table with ECG stickers on your chest and hold your breath briefly while the scan is taken. The scan itself takes only a few minutes.
Understanding the results
The result is a calcium score (Agatston score): zero suggests very low risk, while higher numbers indicate more build-up and higher risk. Results are combined with your other risk factors to guide prevention.
Good to know
Risks and limitations
It uses a small amount of X-ray radiation. It measures calcified plaque only, so a low score does not entirely exclude soft, non-calcified plaque, and it does not show whether arteries are currently narrowed.
Education and reference only. This explains the test in general terms and is not medical advice. Always follow the specific instructions from the team arranging your test, and discuss your results with your clinician.
Answers
Coronary Calcium Score: frequently asked questions
Does a calcium score of zero mean my heart is fine?
A zero score means very low calcified plaque and low short-term risk, but it does not guarantee no heart disease. It is one part of the overall risk picture and should be interpreted with your other risk factors.
Is a calcium score the same as a CT coronary angiogram?
No. Calcium scoring simply measures calcium without dye, while a CT coronary angiogram uses contrast to show the artery interior and any narrowing. They are sometimes done together.
Related tests
Other heart test investigations
Sources
Where this is drawn from
- NHS — Tests and treatments
- NICE — diagnostic guidance
- British Cardiovascular Society / relevant professional body
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