Abstract Introduction Recently, the European Society of Cardiology issued new algorithms (SCORE-2 and SCORE2-OP) to estimate the 10-year risk of atherosclerotic cardiovascular disease (ASCVD). CACS has been shown to reclassify a significant proportion of patients when applied on top of several scores, but data on its use with these new algorithms are lacking. The aim of this study was to assess the risk reassignment that can be attained by using CACS as a risk modifier of the SCORE-2 / SCORE2-OP classification, in patients referred for coronary CT angiography (CCTA). Methods Individuals without diabetes or known ASCVD were included in a single center registry of patients undergoing CCTA for suspected coronary artery disease (CAD). The 10-year risk of cardiovascular disease was calculated for each patient using SCORE-2 (ages 40–69) or SCORE2-OP (ages 70–89), and categorised as low-to-moderate, high, or very-high risk, according to guideline-recommended age-specific thresholds. CACS was considered to reclassify risk one level downward if = 0 in high or very-high risk patients, and reclassify risk upward if >100 (or >75th percentile) in those with low-to-moderate risk, or >1000 in those with high-risk. Results A total of 529 patients (43% men, mean age 63±10 years) were included, of which 13% (n=69) were active smokers. The mean systolic blood pressure and non-HDL-C values were 137±18 mmHg and 140±37 mg/dL, respectively. A total of 47 patients (9%) had obstructive CAD on CCTA, classifying them as very-high risk. In the remainder 482 patients without obstructive CAD, the median CACS was 8 (IQR 0–80 AU), with 194 patients (40%) having CACS = 0, and 111 (23%) presenting CACS values ≥100. The proportion of patients classified as low-to-moderate risk, high risk, and very high risk was 36%, 46% and 19% using the SCORE-2 / SCORE2-OP algorithm. Using CACS would reclassify 150 patients (31%): 107 patients (22%) downward, and 43 patients (9%) upward. The extent of risk reclassification conveyed by CACS was 33% in patients assessed with SCORE-2, and 25% with SCORE-2 OP (p=0.082). Overall, most of the risk reassignment (42%, n=93) would occur in patients originally classified as high-risk – Fig. 1. At the time of testing, 32% (n=61) of patients with CACS = 0 were being treated with statins, whereas 52% (n=58) of those with CACS ≥100 were not. Conclusion Even when the most recent SCORE-2 / SCORE-2 OP algorithms are used, risk refinement with CACS leads to the reclassification of nearly one third of the patients undergoing CCTA, mostly from downgrading risk. This opportunistic use of CACS may be employed to improve the allocation of primary prevention therapies. Funding Acknowledgement Type of funding sources: None.