Managed Care Organizations' providers are required to register their National Provider Identifier (NPI) numbers with the Department of Public Welfare (DPW). The link below provides instructions for registering NPI numbers with DPW (MA Bulletin 99-06-14).
http://www.dpw.state.pa.us/PubsFormsReports/NewslettersBulletins/003673169.aspx?BulletinId=1536