What Is A Medicare Crossover Claim? 
Medicare crossover claims occur when you have original Medicare and a Medicare supplement , also known as Medigap . When you see a medical provider -LRB- doctor , lab , hospital , clinic , etc -RRB- and have original Medicare your provider files your claim with Medicare . Once Medicare completes the adjudication process and approves the claim they transmit it to your Medigapp carrier by way of crossover . 