What is the accuracy of a Coronary Artery Calcium (CAC) score?

From the Guidelines

A coronary calcium score is a highly accurate and reliable non-invasive test for detecting calcified plaque in coronary arteries and predicting future cardiovascular events, with studies such as Shaw et al 1 demonstrating its ability to independently predict death and myocardial infarction. The test has a high sensitivity of approximately 85-95% for detecting significant coronary artery disease, as seen in the MESA study 1, and provides excellent risk stratification, with a score of zero indicating very low risk (less than 1% annual risk of cardiac events), while scores above 300 indicate high risk (over 2% annual risk). Some key points to consider when interpreting coronary calcium scores include:

• The accuracy of the test improves when combined with other risk factors like age, gender, cholesterol levels, and blood pressure, as demonstrated by Polonsky et al 1 who used the CAC score in conjunction with conventional FRS to evaluate 5,878 asymptomatic men and women.
• The test uses CT scanning without contrast to measure calcium deposits, quantifying them as Agatston units, and exposes patients to a small amount of radiation (about 1-2 mSv).
• While excellent at detecting calcified plaque, it cannot identify non-calcified soft plaque that may also cause heart attacks, as noted in the AHA/ACC/AACVPR/AAPA/ABC/ACPM/ADA/AGS/APhA/ASPC/NLA/PCNA guideline on the management of blood cholesterol 1.
• The test may occasionally produce false positives in older patients who naturally have more calcium buildup, highlighting the importance of considering patient demographics and medical history when interpreting results. Despite these limitations, coronary calcium scoring remains one of the most reliable non-invasive methods for assessing coronary artery disease risk, and its use is supported by recent guidelines, such as the AHA/ACC/AACVPR/AAPA/ABC/ACPM/ADA/AGS/APhA/ASPC/NLA/PCNA guideline on the management of blood cholesterol 1, which suggests that patients with a 10-year risk of 5% to 7.5% (borderline risk) in the presence of risk-enhancing factors may benefit from a CAC score prior to initiating statin therapy.

From the Research

Accuracy of Coronary Calcium Score

The accuracy of a coronary calcium score is a topic of interest in the medical field, with various studies examining its reliability and effectiveness in predicting cardiovascular events.

• A study published in 2021 in the journal Coronary Artery Disease found that a coronary artery calcium (CAC) score > 0 was associated with an increased risk of major adverse cardiovascular and cerebrovascular events (MACE) compared to a CAC = 0 in both asymptomatic and symptomatic populations without established coronary artery disease 2.
• Another study published in 2021 in the journal Cureus highlighted the clinical relationship between coronary artery calcium and the development of cardiovascular events, concluding that the CAC score is a reliable indicator of coronary artery disease 3.
• A 2025 study published in the Journal of Cardiovascular Computed Tomography demonstrated the prognostic value of predicted CAC scores for major adverse cardiovascular events, with areas under the curve (AUCs) ranging from 0.74 to 0.82 for different CAC categories 4.
• The Journal of the American College of Cardiology published a review in 2018 summarizing evidence concerning CAC, including its pathobiology, modalities for detection, predictive role, and use in prediction scoring algorithms, concluding that CAC scoring is a widely available, consistent, and reproducible means of assessing risk for major cardiovascular outcomes 5.
• A 2021 study published in Atherosclerosis examined the prognostic significance of CAC among statin users and non-users, finding that CAC scoring retains robust risk prediction in statin users, although the relationship between CAC density and outcomes may be slightly weaker in statin users 6.

Key Findings

• The presence of CAC is associated with an increased risk of cardiovascular events, including MACE and all-cause mortality.
• CAC scoring is a reliable indicator of coronary artery disease, particularly in asymptomatic individuals.
• The predictive performance of CAC components, including CAC area, volume, and density, can provide valuable information for risk assessment.
• CAC scoring retains its prognostic value in statin users, although the relationship between CAC density and outcomes may be affected by statin use.