The percentage of claims using the new Medicare Beneficiary Identifier number instead of the old HICN continues to rise. “For the week ending March 1, providers submitted 67 percent of fee-for-service claims with the MBI,” the Centers for Medicare & Medicaid Services reports. That’s up from 62 percent for the week ending Jan. 25. “We encourage you to use MBIs now for all Medicare transactions,” CMS says.