Medicare Transitional Care Act of 2012 - Amends title XVIII (Medicare) of the Social Security Act to cover transitional care services for qualified individuals provided by a transitional care clinician acting as an employee of a qualified transitional care entity, such as a hospital (or a critical care hospital), a home health agency, a primary care practice, a federally qualified health center, a long-term care facility, a medical home, an appropriate community-based organization, an assisted living center, or an accountable care organization.