A coronary calcium score is a number from a CT scan that measures calcified plaque in the arteries of your heart. At Longevity Benchmark, we review the screening tests sold by longevity programs, and this one most often reaches readers as a number without a decision attached to it.
The scan itself is unusually undemanding: it takes under five minutes, requires no contrast dye, and delivers a radiation dose that a review by Sandfort and Bluemke puts at typically less than 1.5 millisieverts (mSv). Its value to you lies in the risk band a clinician can act on.
The Verdict
What a Coronary Calcium Score Measures
The score measures calcified plaque, and only calcified plaque. Arteries damaged over years accumulate deposits, and older deposits take up calcium, which shows up bright on a CT scan. The scanner counts every deposit denser than 130 Hounsfield units (HU), a scale of how strongly tissue blocks X-rays, then weights each one by how dense it is. Sandfort and Bluemke describe the weighting as a factor of 1 for peak densities of 130 to 199 HU, rising in steps to a factor of 4 above 400 HU. Those weighted areas are summed into the Agatston score.
That method has a consequence readers rarely hear. Newer, softer plaque carries no calcium yet and contributes nothing to the score. A calcium score of zero therefore says that nothing has been accumulating long enough to calcify, which is different from saying the arteries are clean.
What Each Score Band Means
Scores fall into four bands that map onto four levels of risk. The table below uses the bands as Sandfort and Bluemke tabulate them. Other published sources put the boundaries a point either side, so a score sitting right on a cut-point is not the finding. The band you land in is.
| Agatston score | What the scan found | How the risk reads |
|---|---|---|
| 0 | No calcified plaque was found | Very low risk |
| 1 to 100 | A small amount of calcified plaque | Low risk |
| 101 to 400 | A moderate amount of calcified plaque | Increased risk |
| Above 400 | A large amount of calcified plaque | Increased probability of myocardial ischemia |
A zero is the result with the most evidence behind it. The meta-analysis Sandfort and Bluemke summarise found a cardiovascular event in 0.47% of patients scoring zero, which is why the finding gets quoted so heavily by the programs that sell the scan. The same review reports that the score predicts major cardiovascular events better than the Framingham risk score, C-reactive protein, or carotid intima-media thickness. Our page on high-sensitivity C-reactive protein covers what that second marker does and does not add on its own.
How Age and Sex Change the Same Score
The raw number means different things at different ages, and reading it without that context is the most common way a result gets misread. Calcium accumulates with age in almost everyone, so a modest score in an older adult is ordinary and the same score in a younger one is not. A 45-year-old man with a score of 90 sits far above his peers. A 75-year-old with the same 90 sits below the middle of his.
The fix is a percentile. The CAC Score Reference Values tool from the Multi-Ethnic Study of Atherosclerosis (MESA) returns the 25th, 50th, 75th and 90th percentiles for your age, sex and ethnicity, and will place an observed score against them. Its reference population is MESA participants aged 45 to 84 who were free of clinical cardiovascular disease and treated diabetes at baseline, which is also the population the percentile is valid for. In the guides we publish here, a reader who arrives holding only the raw number is the single most common version of this question, and the percentile usually turns it into a decision.
Where the Guidelines Disagree on Calcium Scoring
Two respected bodies read the same test differently, and both readings are defensible. The U.S. Preventive Services Task Force (USPSTF) graded the addition of a calcium score to standard risk assessment an I in 2018, meaning the evidence was insufficient to judge it. The ACC and AHA moved the other way in 2026. Our page on longevity screening sets out that disagreement in full, alongside the other graded and ungraded tests a longevity panel bundles together.
The practical effect of the I grade is financial. Under the preventive care benefits rules, only Grade A and B services are covered without cost sharing by most non-grandfathered US plans. A calcium scan usually falls outside that protection and is billed to you. Coverage still varies, and a scan ordered by a physician to settle a specific treatment decision is treated differently from one bought as a screen. Ask your insurer which CT code your clinic bills before you book.
Whether the Score Can Be Lowered
The score is not a target to bring down, and treating it as one leads people to repeat a scan that changes nothing. Calcified plaque is old damage that has hardened in the artery wall. It does not clear the way an ApoB number falls after starting treatment, and the score commonly holds steady or climbs in people whose treatment is working exactly as intended.
The number exists to trigger a decision. Once a score has moved you onto lipid-lowering treatment and tighter blood pressure control, the markers that tell you whether that treatment is working are the ones you can actually move. Our guide to ApoB covers the one most directly tied to the plaque that is still forming.
Who Should Skip a Calcium Scan
Adults under 45 get the least from it. Calcium takes years to build, so a zero in that decade carries much weaker reassurance than the same result at 60. North Suffolk Cardiology at Stony Brook Medicine states the point plainly, putting the practical floor at 45 because a zero below that age is not as predictive of low risk. A younger adult worried about family history is better served by lipoprotein(a) and ApoB, both of which are informative decades before any calcium appears.
Two other groups should skip it. Anyone already on a statin for a known indication has little to gain, because the result will not change the treatment they are already receiving. Anyone with chest pain or breathlessness on exertion needs a different test, since a calcium score is built for people without symptoms and cannot show the degree of narrowing causing them.
We would change this answer on one condition. If a trial showed that scanning adults under 45 changed what happened to them, rather than only changing what was measured, the age floor above would move. No such trial has reported.
Ask your clinician whether a treatment decision is genuinely open for you before you book a coronary calcium score. That answer decides whether the scan is worth having.
Frequently Asked Questions
What is a coronary calcium score test?
A coronary calcium score test is a computed tomography (CT) scan of the heart that measures calcified plaque in the coronary arteries. It takes under five minutes, uses no contrast dye, and needs no needle. The scanner finds deposits denser than 130 Hounsfield units, a measure of how bright tissue appears on CT, then multiplies the area of each deposit by a factor set by its density. Those values are added into one number, the Agatston score. The result measures arterial damage that has already happened. It does not predict a blockage today.
What is a good coronary calcium score?
Zero is the best result, and it means no calcified plaque was found. In the bands Sandfort and Bluemke tabulate, 1 to 100 is low, 101 to 400 is increased, and above 400 is the top band. Those bands are not the whole answer, because the same number carries different weight at different ages. A score of 90 in a 45-year-old man sits well above his age group. The same 90 in a 75-year-old is unremarkable. Ask for your percentile alongside the raw number.
What does a coronary calcium score of 0 mean?
A score of zero means the scan found no calcified plaque in your coronary arteries, and it carries the strongest prognosis of any result. In a meta-analysis summarised by Sandfort and Bluemke, a cardiovascular event occurred in 0.47% of patients with a score of zero. That is the finding programs are referring to when they call it the power of zero. It is not a guarantee. The scan cannot see softer plaque that has not calcified yet, so a zero in a person with chest pain does not rule out disease and should not end the conversation.
How do I lower my coronary calcium score?
You generally do not, and treating the number as a target misreads what it measures. Calcified plaque is scar tissue in the artery wall, and it does not clear the way a cholesterol number falls after a change in diet or a statin. The score commonly holds steady or rises even in people whose treatment is working. The score exists to trigger a decision: whether to start or intensify lipid-lowering treatment, and how hard to push blood pressure. Track your apolipoprotein B (ApoB) and blood pressure to see whether treatment is working, and treat the calcium score as the reason you started rather than the scoreboard.
Is a coronary calcium score covered by insurance?
Usually not as a no-cost preventive service. The U.S. Preventive Services Task Force graded the addition of a calcium score to standard risk assessment an I in 2018, meaning the evidence was insufficient to assess it. Only Grade A and B services are covered without cost sharing under most non-grandfathered US plans, so an I-graded test falls outside that protection. Coverage still varies by plan and by whether a physician orders it for a specific decision rather than as a screen. Ask your insurer about the specific CT code your clinic will bill before you book.
How often should you repeat a coronary calcium score?
Most people should not repeat it on a schedule. A repeat scan only earns its radiation if the result would change a decision you have not already made. Someone who scored zero at 50 and declined a statin may reasonably rescan years later to see whether calcium has appeared. Someone already on treatment for a score of 300 gains little, because the treatment is not going to change based on the new number. Ask what decision the second scan would settle before you agree to it.
Does a coronary calcium score use contrast dye?
No. A calcium scan is done without contrast, which is one reason it is quick and carries no risk of a contrast reaction or a burden on the kidneys. People asking about dye usually mean a coronary computed tomography angiogram (CCTA). That scan injects iodinated contrast through a vein to show the inside of the artery. Our page comparing a coronary calcium score and a CT angiogram covers which of the two answers which question.
Can you get a calcium score in your 30s?
You can, and it rarely helps. Calcification takes years to accumulate, so a zero in a 35-year-old carries much less reassurance than the same result at 60. North Suffolk Cardiology at Stony Brook Medicine puts the practical floor at 45, noting a score of zero below that age is not as predictive of low risk. A younger adult with a strong family history is better served by measuring lipoprotein(a) and ApoB, both of which are informative decades before calcium appears. Our guide to lipoprotein(a) covers the once-in-a-lifetime test the cardiology guidelines now ask for.
Related
- Coronary calcium score vs CT angiogram — which of the two scans answers which question
- Longevity screening — the graded tests against the ungraded panel extras
- Lipoprotein(a) — the inherited risk marker the 2026 guideline asks every adult to measure once
- ApoB — the particle count that tracks the plaque still forming
- High-sensitivity CRP — the inflammation marker programs pair with a calcium score
- Full-body MRI scan — the other imaging test longevity programs sell