Coronary calcium score
Read Your Scan Editorial Team·Last updated
Written from published radiology references and reviewed for plain language. Not written or signed by a physician, and not a diagnosis. How we write these pages →
In plain language
A number summarising how much calcium has built up in the heart's own arteries on a dedicated CT. Zero means none was detected; higher numbers indicate more hardened plaque, and the score is used alongside your other risk factors rather than on its own.
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Where you'll see this
The impression of a cardiac CT, and sometimes noted incidentally on a chest CT.
Your report may word it “Agatston score”, “Calcium score” or “CAC score”. These mean the same thing.
Questions worth asking your doctor
- What category did I get, and what does that category normally lead to?
- What is the recommended next step for this category — waiting, another scan, or a biopsy?
- Who decides the timing, and what should I do if my symptoms change before then?
How often does this turn up?
The coronary calcium score is produced by a quick CT of the heart, done without contrast, and it is used to refine cardiovascular risk in people without symptoms. It measures calcified plaque in the walls of the coronary arteries and converts it into a single number. It also turns up as an incidental observation on chest CTs done for other reasons, where the calcification is noted without being formally scored.
Does it mean something is wrong?
The number is a measure of how much calcified plaque is present, not a measure of blockage and not a prediction. A score of zero is genuinely reassuring in someone without symptoms, and it is the main reason the test is used at all — it can move someone out of an intermediate risk band and away from treatment they did not need. Higher scores indicate more plaque and a higher risk over the following years, but they do not say that any artery is narrowed, and they cannot diagnose the cause of chest pain. Anyone with symptoms needs a different test; this one is for people who have none.
What to do with it
The result is used as one input into a risk conversation rather than as a diagnosis. A zero score often supports doing nothing beyond the usual advice. A raised score usually shifts the discussion towards treating cholesterol and blood pressure more actively, and towards the things that reduce risk generally. It does not by itself lead to a stent or an angiogram, because it says nothing about whether any artery is actually narrowed.
Frequently asked questions
- What is a good calcium score?
- Zero is the most reassuring result and means no calcified plaque was detected. Scores are usually reported in bands rather than treated as precise, and what any given band means for you depends on your age, sex and other risk factors — which is why it is interpreted with a doctor rather than read alone.
- Does a high score mean my arteries are blocked?
- No. The score measures calcium in the artery walls, not narrowing of the channel inside them. Someone can have a high score with no significant narrowing at all. Assessing blockage requires a different test.
- Should I have this test if I have chest pain?
- It is not the test for that. The calcium score is designed for people without symptoms, to refine long-term risk. Chest pain needs an assessment aimed at what is causing it, which your doctor will arrange differently.
Standard scoring systems
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