Primary care practices can participate in both the Medicare Shared Savings Program and Comprehensive Primary Care Plus model in certain circumstances, the Centers for Medicare & Medicaid Services said Friday in an update to Frequently Asked Questions on the model. Practices in Tracks 1, 2 or 3 of the MSSP or considering those tracks may participate in the CPC Plus model if eligible, the agency said. Practices participating in the Accountable Care Organization Investment Model, Next Generation ACO Model or other shared savings programs may not participate in the CPC Plus model, CMS said. It plans to limit the number of CPC Plus practices in ACOs to 1,500.