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Instalab ResearchA coronary artery calcium (CAC) score measures calcified plaque in the arteries that supply your heart. The test uses a quick CT scan and produces a number, called an Agatston score, that reflects how much calcium has built up. Zero means no detectable calcified plaque. Higher numbers mean more.
The catch is that calcium accumulates over a lifetime. So the same score carries very different meaning depending on whether you are 35 or 75. Research now provides age-, sex-, and race-specific reference ranges that let doctors (and patients) interpret a score relative to what is typical and what is risky for someone like you.
The short answer: rare in your 30s, common by your 50s, and nearly universal past 75.
Among adults aged 30 to 45, any detectable calcium is uncommon. Studies show that roughly 26% of White men, 16% of Black men, 10% of White women, and 7% of Black women in this age range have any calcium at all. In a slightly broader clinical group (ages 30 to 49) with higher baseline risk, about 34% had some calcium, and around 7% had scores above 100.
By your 50s and 60s, calcium becomes a routine finding. The question shifts from "Do you have any?" to "How much, and how does it compare to your peers?"
Past 75, calcium is the norm. Between 89% and 96% of adults in this age group have detectable calcium, and roughly 63% have scores above 100. At this stage, a "high" absolute number is almost expected, and the raw score alone tells you surprisingly little.
Yes, and significantly. In young adults under 50, even a very small amount of calcium (scores of just 1 to 19) is linked to a two- to fivefold increase in coronary heart disease events, cardiovascular events, and early mortality. A score of 100 or higher in this age group carries particularly high long-term risk.
Because calcium is so uncommon at younger ages, even a modest amount can place you above the 90th percentile for your age, sex, and race. Updated reference data shows that for women aged 30 to 45 and many men in that range, any calcium at all already represents an outlier result.
One important caution: a zero score in a young, symptomatic person does not reliably rule out dangerous blockages. Research on adults under 40 with symptoms found that up to 58% of cases with significant obstructive coronary artery disease had a calcium score of zero. If you are young and having chest pain or other concerning symptoms, a clean calcium score is not a guarantee.
For adults roughly 40 to 75, a calcium score of zero is one of the most reassuring findings in cardiovascular screening. Studies show that people in this age range with a score of zero have very low rates of coronary heart disease and cardiovascular death. In fact, cancer often becomes the leading cause of death in this group rather than heart disease.
As scores climb, the picture shifts. Scores in the 100 to 400 range begin to make cardiovascular disease the dominant mortality risk, and this transition happens at lower scores in younger people compared to older ones. In other words, a score of 150 is more consequential at 50 than at 70.
It is, but the value lies at the low end of the scale. When nearly everyone your age has calcium, a high score does not distinguish you from your peers. What does stand out is having very little or none.
Research from large cohort studies shows that older adults with scores in the 0 to 9 range, or below the 25th percentile for their age group, still represent a meaningfully lower-risk subgroup. Adults in their late 70s and 80s with a score of zero tend to have better markers of overall health, including less arterial stiffness, better lung function, and stronger physical performance. In this context, a zero is not just a heart number. It is a marker of what researchers call "healthy aging."
Updated percentile tables for adults 75 and older also reveal that prior tools underestimated what counts as a high score in this group, particularly for Black women. The 75th percentile in older populations corresponds to much higher calcium levels than earlier calculators suggested.
Absolutely. A raw Agatston score of 50 means something very different for a 38-year-old Black woman than for a 72-year-old White man. Percentile-based interpretation accounts for that.
Online calculators now cover a wider age range than before. Updated tools provide age-, sex-, and race-specific percentiles for adults as young as 30 to 45 and for those 75 and older, filling gaps left by the classic calculator that covered ages 45 to 84. Some tools go a step further and calculate a "coronary age," translating your risk profile and calcium score into an equivalent arterial age. If you are 48 but your arteries look like a typical 60-year-old's, that framing can make the result more concrete than a percentile.
Research also shows that as people age, calcium tends to spread across more vessels and becomes more diffuse, which is another reason that simple score thresholds become less informative over time.
The most practical thing you can do with a calcium score is interpret it in context, not in isolation. Here is how to put the research to work:
Your calcium score is not a verdict. It is a data point that gains meaning only when placed alongside your age, demographics, symptoms, and the rest of your health picture. The research makes one thing clear: the same number can tell very different stories depending on when in life it appears.