GHP May Be Primary to Medicare

30.3 - GHP May Be Primary to Medicare (Rev. 11550; Issued: 08-12-22; Effective: 10-13-22; Implementation:10-13-22) Where Medicare is indicated as primary payer on the Part A or Part B electronic or paper claim, the A/B MAC and DME MAC assumes, in the absence of evidence to the contrary, that there is no other primary coverage and processes the claim accordingly. If CWF indicates that Medicare is secondary, the A/B MAC notifies the MSP Contractor via ECRS to develop to determine if there is another payer primary to Medicare.