What do Medicare Beneficiary Identifiers (MBIs) mean for other payers?

Medicaid & supplemental insurers

We've given State Medicaid Agencies and supplemental insurers the MBIs for Medicaid-eligible people who also have Medicare. 

We’re using a crosswalk that shows you HICNs and the MBIs that go with them. So, if you use HICNs for crossover claims processing, you also have access to MBIs. For crossover claims processing, we’ll keep sending you state ID numbers like we've been doing.

Private payers

For non-Medicare business, private payers won’t have to use the MBI. If you're a supplemental insurer, we’ll continue using your unique numbers to identify your customers, but now, you must use the MBI for any Medicare transactions.

Even though we’re using MBIs for claims and other Medicare business, this change shouldn’t affect how you're using Social Security numbers (SSNs) to identify and verify your members.  

You don’t need to change your members’ ID numbers unless those ID numbers include whole or parts of their SSNs. We urge you to keep using the unique identifiers that you’ve been using and not to include MBIs on your members’ ID cards.

If you send a HICN now, we won’t send you a new transaction reply code. MARx is sending you the same transaction code (008) when a health insurance claim number can’t be found.

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