What modifier is needed for a 99214 visit that requires a 93880 and 93306 to be performed?

For a 99214 visit that also requires the performance of a 93880 (Carotid Doppler) and 93306 (Echocardiography), you would typically use modifier 25. This modifier indicates that a significant, separately identifiable evaluation and management service was performed on the same day as the diagnostic procedure. It ensures that the E/M service and the procedures are appropriately reimbursed without being bundled together.