Most people who get a coronary artery calcium score and see a small number may walk away feeling reassured. But a new study from Mount Sinai shows that calcium score misses the risky low-density non-calcified plaque. The only blood marker that independently tracked with that plaque was Lipoprotein(a), or Lp(a), a genetically inherited risk factor that most people still do not test for.
Key finding
Lp(a) is the only biomarker that independently predicts low-density non-calcified plaque
A little bit of background
A large share of heart problems begin with plaque buildup inside the coronary arteries. If plaque does not build up, heart attack risk stays much lower. The challenge is that the tests most people rely on, like standard cholesterol panels, do not directly show how much plaque is already sitting in the artery wall.
That is part of why calcium score became so popular. It is quick, relatively affordable, and widely available. If calcium is present in your coronary arteries, that means plaque is present too. That can be very useful for pushing someone toward earlier lifestyle changes or medications when needed. If you already have a calcium score, you can check how it compares to others your age.
Challenges with calcium score
Calcium score is useful, but it has important blind spots. First, it only sees calcified plaque. It does not see the full non-calcified plaque burden. Coronary CT angiography can show a much fuller picture of what is happening in the artery wall.
Second, calcium score does not see soft plaque well, and soft plaque is often the more vulnerable kind. In the Mount Sinai study discussed below, calcium score tracked total plaque burden, but it had no independent association with low-density non-calcified plaque, the more rupture-prone subtype.
Third, a zero calcium score does not mean zero plaque. Prior CT angiography studies have shown that some people with CAC = 0 still have non-calcified plaque, which is especially relevant in younger adults where plaque may not have had time to calcify yet.
Fourth, calcium score can become harder to interpret once treatment starts. Statin therapy can increase coronary calcification while stabilizing plaque, so a rising calcium score over time does not always mean your arteries are getting biologically more dangerous.
Mount Sinai's study
Researchers at Mount Sinai's Icahn School of Medicine looked at 547 asymptomatic adults who had no known heart disease. These were primary prevention patients, meaning the goal was to catch risk before anything goes wrong. Each patient received a coronary CT angiography, along with bloodwork for Lp(a), LDL particle concentration (LDL-P), high-sensitivity CRP (hsCRP), and a coronary artery calcium score.
A coronary CT angiogram captures the full plaque picture in the coronary arteries, while a calcium score captures only the calcified portion. The researchers asked a simple question: which of these markers most directly tracks with the soft, riskier plaque?
Their main findings
The study found that calcium score was the strongest predictor of total plaque burden, including both calcified and non-calcified plaque. That matters. But calcium score had no independent association with low-density non-calcified plaque.
Lp(a), the genetically inherited lipoprotein marker, was the only biomarker independently associated with low-density non-calcified plaque after adjustment for age, sex, and the other risk markers in the model. It was also associated with higher arterial narrowing and a higher remodeling index, both signals of more concerning plaque behavior.
LDL-P and hsCRP, two commonly discussed risk enhancers, did not show significant independent associations with plaque subtype in the multivariable model. Once Lp(a) and calcium score were in the picture, those markers added much less.
What is Lp(a) and why is it overlooked?
Lp(a) is a lipoprotein particle that is largely determined by your genes. Unlike LDL cholesterol, which can move with diet, weight loss, and statins, Lp(a) levels are mostly set early and stay fairly stable through life. The American Heart Association notes that roughly 20% to 30% of people worldwide have elevated levels.
Despite being recognized as an independent heart disease risk factor for decades, Lp(a) is still not part of routine testing for many people. A lot of patients only hear about it after a cardiac event, or never at all.
That is starting to change. In the updated 2026 cholesterol guidelines from American Heart Association, Lp(a) is recommended to be measured at least once in adulthood. Studies like this one are a big reason why. If your calcium score looks okay but your Lp(a) is high, you may still be carrying more risk than you think.
What you can do right now
If you want a direct-pay option, Own Your Labs offers an Lp(a) test for $35.
- Get tested for Lp(a) at least once. Because it is genetically determined, one measurement is often enough.
- Treat a clean calcium score as useful information, not the full story.
- If your Lp(a) is high, talk with your doctor about tightening the controllable factors: LDL cholesterol, blood pressure, exercise, sleep, and diet.
- If your family history, labs, or symptoms do not match a reassuring calcium score, consider coronary CT angiography to see the full plaque picture.
The bottom line
Heart health is more complex than a single blood test or a single scan. Calcium score is useful. LDL is useful. But neither tells the whole story on its own.
Getting your Lp(a) checked once, keeping your traditional risk factors under control, and using coronary CT angiography when you need a fuller answer can put you in a much stronger position to act early. That is the real goal: not just reassurance, but clarity.
Confidence in your heart health
An advanced heart CT scan that helps you see what is actually happening inside your coronary arteries, so you can act early and with more confidence.