Prospective studies of CAC screening do show improvement in the net reclassification index.[29] The use of CAC screening may result in overtreatment and unnecessary radiation exposure. No significant benefit in the incidence of MI, CVD, or overall mortality has been demonstrated with the addition of CAC scoring to a traditional risk score. Even in retrospective studies showing a favorable net reclassification index, many more patients were incorrectly reclassified to a higher risk category than were correctly The risk of radiation exposure from CAC scoring is not negligible. Although not included in our systematic evidence review and, thus, not considered in determining the strength of this recommendation, Kim et al. (2009) estimated a single CAC screening at the age of 40 would result in a lifetime excess cancer risk of 9 per 100,000 for males and 28 per 100,000 for females.[31] As this is a Reviewed, Not changed recommendation, the Work Group systematically reviewed evidence related to this recommendation.[29] The Work Group s confidence in the quality of the evidence was low. Other considerations regarding this recommendation include patient preference in understanding the risk and benefits of CAC. Patient values and preferences vary but often align with a desire for more testing. The Work Group encourages a patient-provider conversation regarding the risk of over-diagnosis, cost, and radiation exposure in relation to a very small potential net benefit associated with CAC testing. Thus, the Work Group decided upon a Weak against recommendation. In the absence of individual patient data, it is unclear which patients will benefit from CAC testing. The Work Group recommends prospective studies designed to assess the benefit of adding CAC to traditional risk scoring systems for the prediction of future atherosclerotic CVD endpoints. Recommendation 5. We suggest against the routine use of additional risk markers (e.g.