In order to enhance Medicaid efforts to ensure that the program is providing quality, affordable health care for all Americans, the United States Congress included provisions in the Patient Protection and Affordable Care Act of 2009 that mandates changes in Medicaid rules for enrolling providers and submitting claims. Starting January 1, 2011, Medicaid will require that all providers who must obtain an NPI include their NPI on all claims submitted to Medicaid. This will include all claims from these providers, whether submitted on paper or electronically. The Medicaid provider number will be allowed to accompany the NPI on claims; however, claims that do not contain the NPI will be denied.
Source: Health Care Alerts & Provider Alerts Messages July 2010 bulletin