A standard cholesterol panel tells you about the particles circulating in your blood. A coronary artery calcium (CAC) scan looks somewhere else entirely: at the walls of the arteries that supply your heart, and whether plaque has already started to harden there.
That difference is why the test is useful, and it is also why a CAC score is easy to misread. This guide covers what the scan measures, what the score ranges mean, who it tends to help, and what it cannot tell you.
At YoungerMeMD, a CAC score is part of the Cardio Res-Q Enhanced Assessment, alongside a CIMT ultrasound and a full cardiovascular lab panel.
Key takeaways
- A CAC scan is a quick, low-radiation CT that measures calcified plaque in the heart's arteries, with no injection or dye.
- A score of zero means no calcified plaque was seen, and higher scores mean more plaque and higher risk.
- The scan is most useful when the result would change a decision, such as when calculated risk is borderline or intermediate.
- It cannot see soft plaque, does not measure narrowing and is not a test for symptoms.
- Treatment does not bring the score down, and repeat scans are not routine.
What the scan actually measures
Plaque in a coronary artery does not start out hard. Cholesterol-carrying particles lodge in the artery wall, the wall reacts, and over years part of that plaque calcifies. A CAC scan is a non-contrast CT of the chest, timed to your heartbeat, that detects that calcium and adds it up.
The result is reported as an Agatston score: a single number that reflects how much calcium is present and how dense it is. Many reports also give a percentile, which compares your score with people of the same age, sex and ethnicity.
The practical details:
- No injection and no contrast dye. You lie on the scanner table, hold your breath for a few seconds, and the images are taken.
- Low radiation. Specialist guidance for calcium scoring targets an average of about 1 to 1.5 mSv, and modern scanners often use less.1
- Quick. The visit is short, most of it check-in and positioning.
What the score ranges mean
Score bands vary slightly between reports, but these are the ones most commonly used:
| CAC score | What it generally means | Band guide |
|---|---|---|
| 0 | No calcified plaque detected. Short-term risk of a heart event is low for most people. | CAC score 0 |
| 1 to 99 | Calcified plaque is present. Atherosclerosis has started, even if the amount is small. | Calcium score 1 to 99 |
| 100 to 399 | A moderate plaque burden. Under current US cholesterol guidance, this generally supports lipid-lowering treatment. | Calcium score 100 to 399 |
| 400 to 999 | A high plaque burden and meaningfully higher risk. This usually calls for more intensive risk reduction, but without symptoms it is not an emergency. | Calcium score 400 and above |
| 1,000 and above | A very high plaque burden. Follow-up is individual and is set with your clinician. | Calcium score over 1,000 |
The percentile matters as well. A score of 50 means something different at 42 than it does at 72. A result at or above the 75th percentile for your age and sex is treated as a significant finding even when the absolute number looks modest.
What a higher score changes
A CAC score does not diagnose a blockage and is not a verdict. What it does is move a risk estimate from a calculation to a measurement.
US cholesterol guidelines have used CAC this way for years. The 2018 AHA/ACC guideline described calcium scoring as a tiebreaker for adults whose calculated risk sat in the middle: a score of zero could support delaying a statin, and a score of 100 or more supported starting one.2 The 2026 ACC/AHA dyslipidemia guideline, which replaced it, keeps CAC in that role and extends it, so that any calcified plaque now counts in favor of lipid-lowering treatment.3
In practice, a score above zero usually means the conversation moves from "should we act?" to "how firmly?" That covers lipid targets, including ApoB, blood pressure, blood sugar and insulin resistance, and the lifestyle factors that drive plaque growth.
Who it may help
A CAC score is most useful when the answer would change what you do. That usually means:
- Adults in their forties or older whose calculated heart risk falls in the borderline-to-intermediate range, where treatment decisions are genuinely uncertain.
- People with a family history of early heart disease who want to know whether it is showing up in their own arteries.
- People with a high Lp(a) or ApoB result, where the question is how much plaque has already formed.
- Anyone weighing whether to start, or stay on, a cholesterol-lowering medication who wants a direct look before deciding.
It is usually less useful for people whose risk is already clearly high. For example, someone who has had a heart attack or stent does not need a calcium score to justify treatment. At the other end, for most people under 40 it is unlikely to find anything even when risk factors are present.
What it cannot tell you
- It does not see soft plaque. Plaque that has not calcified is invisible to the scan. A low score is not proof that the arteries are clean.
- It does not measure narrowing. A high score means a lot of plaque, not necessarily a blocked artery. Whether any artery is narrowed is a separate question with separate tests.
- It is not a test for symptoms. Chest pain, pressure, or shortness of breath on exertion need a clinical evaluation, not a screening scan. If you have symptoms now, see when to seek care.
- Treatment does not erase it. Calcium scores tend to rise over time, and some treatments that stabilize plaque can nudge the score up. A repeat scan is read with that in mind.
How the scan fits into Cardio Res-Q
The CAC scan is performed at an outside imaging facility that you choose near you; scheduling and how fast results come back depend on that facility. If you already have a calcium score from elsewhere, it can be used. Otherwise your provider orders the scan as part of the Enhanced Assessment, and the result is read together with your bloodwork, your CIMT ultrasound and your history. We do not interpret it in isolation.
Repeat scans are not routine. After a score of zero, guidance suggests a rescan several years later; once calcium is present, the score is less often repeated, because the plan is already built on it.
Are You a Candidate for Cardio Res-Q?
Three quick questions about the risk factors we screen for. Your answers stay between you and the clinic.
Frequently asked questions
Is a CAC scan the same as a heart CT angiogram?
No. A calcium scan uses no contrast dye and only detects calcium. A CT angiogram uses an injected dye to show the inside of the arteries, including soft plaque and narrowing. They answer different questions.
Does a high CAC score mean I need a stent?
Not by itself. A high score indicates a large plaque burden, which usually means more aggressive prevention. Stents treat significant narrowing that causes symptoms or is found on other testing; the calcium score alone does not show that.
Is a CAC scan covered by insurance?
Often it is not, because it is a screening test. Patients have reported self-pay prices of about $100 to $200, but that is not a quote. Check the current price with the imaging facility you choose.
How often should the scan be repeated?
It depends on the first result. After a zero, a rescan is typically considered after three to seven years, sooner with diabetes or other strong risk factors. With calcium present, the decision is individual.
I have normal cholesterol. Can my CAC score still be high?
Yes. Cholesterol is one input among several, and a single LDL number can underestimate the number of particles actually reaching the artery wall. That mismatch is one reason the scan is useful.
Related reading
This article is for general education and is not medical advice. A CAC score is interpreted by a clinician alongside your full history and other results. If you have chest pain or other symptoms of a heart attack, call 911.
