Short answer
A coronary artery calcium (CAC) score is a number from a quick, low-dose CT scan that measures calcified plaque in your heart arteries. A score of 0 means no calcium was found. Scores of 400 or above mean extensive plaque and high risk, and clinicians read your number next to your percentile for age and sex.
This guide explains how to read your number and what it changes.
What is a CAC score?
A coronary artery calcium (CAC) score comes from a low-dose CT scan of the heart that detects calcium deposits within the walls of the coronary arteries. Calcium is a marker of atherosclerosis, the plaque buildup process that leads to heart attacks, so a CAC score directly measures the calcified plaque that has already built up, while risk factors like cholesterol and blood pressure only estimate it.
Key Takeaway
Cholesterol numbers estimate your future risk. A CAC score shows you what has already happened inside your arteries. The two together give a far more complete picture than either alone.
What is a good or bad CAC score for your age?
Clinicians read the raw number alongside your percentile for age and sex, so the same score means different things at 45 and at 70. The Agatston score, a single number calculated from the CT scan, falls in these ranges:
- 0: no detectable calcified plaque
- 1 to 99: mild plaque
- 100 to 399: moderate plaque
- 400 or above: extensive plaque, high risk
- 1,000 or above: very high plaque burden
The chart shows where a score falls for people your age. Pick your sex and background, slide to your age, and enter your score if you have one.
At age 60, the middle (50th percentile) score in this group is 0, and the 90th percentile is 102.
Show the numbers
| Age | 25th | 50th | 75th | 90th | Chance of a score above 0 |
|---|---|---|---|---|---|
| 45 | 0 | 0 | 0 | 0 | 7% |
| 50 | 0 | 0 | 0 | 8 | 16% |
| 55 | 0 | 0 | 1 | 38 | 26% |
| 60 | 0 | 0 | 16 | 102 | 36% |
| 65 | 0 | 0 | 54 | 228 | 47% |
| 70 | 0 | 13 | 119 | 391 | 59% |
| 75 | 0 | 49 | 237 | 649 | 73% |
| 80 | 20 | 106 | 370 | 921 | 87% |
| 84 | 46 | 159 | 488 | 1168 | 98% |
Percentiles rank your score against peers in the Multi-Ethnic Study of Atherosclerosis (MESA) who had no known heart disease or treated diabetes at the start. MESA covers ages 45 to 84 and the four groups shown. A percentile ranks you against peers and does not tell you your risk, so go over your number with your clinician. Values come from the MESA reference calculator, based on McClelland et al., Circulation 2006. The scale is logarithmic.
Your score is usually reported alongside an age- and sex-adjusted percentile, since a small amount of calcium is more common, and less concerning, in a 70-year-old than in a 40-year-old with the same raw number.
In the MESA study of 6,814 adults followed for about 11 years, the risk of a heart attack or stroke climbed steadily with each step up in calcium 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.
Source
Budoff MJ, Young R, Burke G, et al. “Ten-year association of coronary artery calcium with atherosclerotic cardiovascular disease (ASCVD) events: the Multi-Ethnic Study of Atherosclerosis (MESA).” European Heart Journal (2018).
View paperSource
Peng AW, Dardari ZA, Blumenthal RS, et al. “Very High Coronary Artery Calcium (≥1000) and Association With Cardiovascular Disease Events, Non-Cardiovascular Disease Outcomes, and Mortality: Results From MESA.” Circulation (2021).
View paperWhat does your CAC score mean for LDL goals?
The 2026 ACC/AHA dyslipidemia guideline ties LDL cholesterol (LDL-C) goals to the score (UIC Drug Information Group summary):
CAC score and LDL-C goals, 2026 ACC/AHA guideline
Source
University of Illinois Chicago Drug Information Group “What are key updates from the 2026 ACC/AHA/AACVPR/ABC/ACPM/ADA/AGS/APhA/ASPC/NLA/PCNA guideline on dyslipidemia management?.” UIC Drug Information Group FAQs (2026).
Getting LDL-C below 70 or 55 often takes more than a statin. Ezetimibe is the usual next step, and a PCSK9 inhibitor is an option when that still isn't enough.
What does a calcium score of zero mean?
A score of zero means no calcified plaque was seen, and it predicts a 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 score reflects your arteries on the day of the scan, and risk factors like elevated LDL, smoking, or diabetes can still lead to plaque developing afterward.
Can you lower your calcium score?
No. Once calcium is deposited, treatment doesn't remove it, so your score won't go down and may keep rising slowly even with excellent treatment. Statins can even add calcium: in a pooled analysis of eight trials that imaged the heart arteries from the inside, 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, the outcome that matters, whatever happens to the calcium number.
Source
Puri R, Nicholls SJ, Shao M, et al. “Impact of Statins on Serial Coronary Calcification During Atheroma Progression and Regression.” Journal of the American College of Cardiology (2015).
View paperAfter a high CAC score, treatment aims to keep the plaque you already have stable and to slow how much more accumulates. The number itself usually holds steady or creeps up.
Who should get a calcium score, and how do you get one?
Mainly people whose next treatment decision is a close call. The 2026 ACC/AHA guideline supports a calcium 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 help:
- Adults with borderline or intermediate cardiovascular risk where the decision to start a statin is a close call
- People with a family history of early heart disease who want more concrete information than family history alone provides
- Anyone who wants to understand their actual plaque burden, beyond their risk factors, before committing to lifelong medication
The test uses low radiation, most regions have it, and many imaging centers offer it as a self-pay test. Prices vary by center, so ask before you book.
Step by step
Get and read a calcium score, step by step
- Time
- About 15 minutes to arrange
Check whether a score would change your decision
It helps most when starting cholesterol medicine is a close call, such as borderline or intermediate 10-year risk. Ask your clinician whether that fits you.
Book the scan at a local imaging center
Many centers offer it as a self-pay test. Ask about the price before you book.
Find your number and your percentile on the report
The report lists the Agatston score and usually an age- and sex-adjusted percentile. Both matter.
Match the score to an LDL goal
Use the ranges in the table above, then ask your clinician which LDL-C number you are aiming for.
Keep treating the cause, whatever the score does
Lowering LDL-C and ApoB cuts heart attack risk even if the calcium number holds steady or creeps up.
Summary
A cholesterol panel estimates your risk of developing plaque. A CAC score measures how much plaque you have right now. A high score doesn't automatically mean a blockage that needs a procedure, and treatment won't lower it. It still ranks among the most useful pieces of information for deciding how aggressively to treat everything else.
Preval Health does not perform imaging. When a calcium score would change your plan, your clinician may recommend one from a local imaging center, alongside the ApoB, Lp(a), and LDL-C testing central to how we assess every patient. A calcium score is also one of the tests worth asking about if you have a family history of early heart disease.