Getting MBIs

How do health care providers & office managers get patients' MBIs?

People with Medicare can look up their MBIs and providers can look up their patients’ MBIs through secure web interfaces that will support quick access to the MBI.

Our Medicare Administrative Contractors (MACs) mailed letters (here’s a sample (PDF)) to all Medicare Fee-For-Service providers to tell you how to use your MAC’s secure portal. You can use the portal to look up MBIs for your Medicare patients who don’t have their MBIs when they come for care. Using your MAC’s portal, you can look up any Medicare patient’s MBI, regardless of where the patient lives. 

If you previously saw a patient and got a claim payment decision based on a claim submission with a HICN before January 1, 2020, look at that remittance advice. We returned the MBI on every remittance advice when a provider submitted a claim with a valid and active HICN through December 31, 2019.

 835 Loop 2100, Segment NM1 (Corrected Patient/Insured Name), Field NM109 (Identification Code)

Page Last Modified:
06/24/2022 08:38 AM