CAC Score: What Your Calcium Score Means

A CAC score comes from a low-dose CT scan of the heart that detects calcium deposits in the walls of the coronary arteries. Calcium marks atherosclerosis, the plaque buildup behind heart attacks.

Cholesterol numbers estimate your future risk. A CAC score shows the calcified plaque that has already built up, and the two together give a fuller picture than either alone.

The Agatston score, a single number calculated from the scan, falls in these ranges. Clinicians read it next to your percentile for age and sex, since a small amount of calcium is more common, and less concerning, in a 70-year-old than in a 40-year-old.

In the MESA study of 6,814 adults followed for about 11 years, the risk of a heart attack or stroke climbed with each step up in score, across ages, sexes, and ethnic groups. People with a score of 1,000 or more had event rates similar to people already being treated for heart disease.

For a score of 1,000 or higher, the 2026 ACC/AHA guideline sets an LDL-C goal below 55 mg/dL. Ask your clinician which LDL-C number fits your score.

No calcified plaque showed up, which predicts low risk over the next 10 years. In MESA, 10-year event rates with a score of 0 were almost all below 5%, even in people with some elevated risk factors. Clinicians often use a zero score to support a more conservative approach to starting medication in someone who is otherwise borderline.

A zero reflects your arteries on the day of the scan. High LDL, smoking, or diabetes can still lead to plaque later.

No. Once calcium is deposited, treatment doesn't remove it, and the score may creep up even with excellent treatment. In a pooled analysis of eight trials, high-intensity statins shrank plaque while making it more calcified, which is thought to make plaque more stable.

Lowering LDL-C and ApoB still cuts the risk of a heart attack, whatever happens to the calcium number.

The 2026 ACC/AHA guideline supports a score for men 40 and older and women 45 and older whose 10-year risk is borderline or intermediate, to help decide whether to start cholesterol medicine. It can also help people with a family history of early heart disease, or anyone who wants to see their actual plaque burden before committing to lifelong medication.

The test uses low radiation, and many imaging centers offer it as a self-pay test. Prices vary, so ask before you book.