The ability to select those who would benefit greatly from statin therapy, as shown by RCTs in primary-prevention populationsS4.4.2-6,S4.4.2-8 and yet to withhold statin therapy in those least likely to benefit would improve specificity.S4.4.2-34 For example, a CAC score of zero in an analysis of pooled US population-based studies accurately discriminated between lower and higher CHD risk in older adults.S4.4.2-19,S4.4.2-27 The BioImage Study in older adultsS4.4.2-15 showed improved detection of individuals not likely to benefit from statins when the CAC score was zero. Selected examples of candidates for CAC scoring who might benefit from knowing their CAC score is zero are listed in Table 8. Clinicians should not down-risk patients who are persistent cigarette smokers, have diabetes mellitus, or have a strong family history of ASCVD, as well as pos- sibly those with chronic inflammatory conditions whose CAC of zero does not rule out risk from 7. In adults at intermediate-risk (predicted 10-year risk of 7.5% to <20%), substantial data indicate how CAC measurement can be effective in mean- ingfully reclassifying risk in a large proportion of In such inter- mediate-risk adults, those with a CAC score 100 Agatston units or CAC 75th percentile appear to have ASCVD event rates suggesting that statin therapy would be beneficial.S4.4.2-17,S4.4.2-23 Those with a CAC of zero appear to have 10-year event rates in a lower range that suggests statin therapy may be of limited value for these patients, with few exceptions including patients with diabetes mellitus, persistent smoking, and family history or premature ASCVD. 