The percentage of claims using beneficiaries’ new MBI numbers is nearing two-thirds. For the week ending Jan. 25, providers submitted 62 percent of fee-for-service claims with the Medicare Beneficiary Identifier number, the Centers for Medicare & Medicaid Services reports. “We encourage you to use MBIs now for all Medicare transactions,” CMS tells providers. Two weeks earlier, CMS had reported the percentage of claims using MBIs at 58 percent.