A coronary calcium score is a CT test that measures calcium in the walls of the coronary arteries — the arteries that supply blood to the heart.
Why is calcium important?
Calcium can develop within atherosclerotic plaque. Finding coronary artery calcium therefore provides evidence that coronary atherosclerosis is already present.
The test is performed using a cardiac CT scan without contrast. The amount of calcium detected is calculated as a numerical result, commonly called a CAC score or Agatston score.
A score of 0 means that no calcified coronary plaque was detected. As the score increases, it generally indicates a greater burden of calcified coronary atherosclerosis.
The calcium score does not show every type of coronary plaque and does not tell us by itself whether a coronary artery is significantly narrowed. It provides a different piece of information: how much calcified atherosclerosis can be detected in the coronary arteries.
This information can be considered together with age, blood pressure, cholesterol, smoking, diabetes and other cardiovascular risk factors when assessing an individual’s cardiovascular risk.
A large study published in 2025 followed more than 66 000 asymptomatic adults for a median of 12.5 years. Higher coronary calcium scores were associated with progressively greater long-term heart failure-related mortality.
The study adds to the evidence that a coronary calcium score can provide information about long-term cardiovascular risk.
