Make Sure to Use MBI Numbers for Medicare Claims Submitted After Jan. 1

Last Updated: Jan 1, 2020


As of Jan. 1, 2020, most Medicare claims submitted with the old HICN numbers will be rejected, no matter what date the service was performed. Be sure to use the 11-digit Medicare Beneficiary Identifiers (MBIs) for claims.

Reject Codes

These reject codes will be used for claims submitted after Jan. 1 that are missing the MBI number:

  • Electronic claims reject codes – Claims Status Category Code of A7 (acknowledgment rejected for invalid information), a Claims Status Code of 164 (entity’s contract/member number), and an Entity Code of IL (subscriber)
  • Paper claims notices – Claim Adjustment Reason Code (CARC) 16 “Claim/service lacks information or has submission/billing error(s)” and Remittance Advice Remark Code (RARC) N382 “Missing/incomplete/invalid patient identifier”

What to Do If a Patient's MBI Number Has Changed

Medicare beneficiaries or their authorized representatives can ask to change their MBIs. Additionally, CMS can change an MBI. Patients can seek care before getting a new card with the new MBI. 

If you get an eligibility transaction error code (AAA 72) of “invalid member ID,” your patient’s MBI may have changed. You can take these steps to obtain the new MBI:

  • Do a historic eligibility search to get the termination date of the old MBI.
  • Get the new MBI from your Medicare Administrative Contractor’s secure MBI look-up tool. In Pennsylvania, the MBI Lookup Tool is available through the Novitasphere portal


CMS says that there are a few exceptions that allow you to use either the HICN or MBI after Jan. 1, such as:

  • Appeals – The HICN or the MBI can be used for claim appeals and related forms
  • Claim status query – The HICN or MBI can be used to check claim status if the earliest date of service on the claim is before Jan. 1.
  • Span-date claims – The HICN can be used for 11X-Inpatient Hospital, 32X-Home Health (home health claims & Request for Anticipated Payments (RAPs)), and 41X-Religious Non-Medical Health Care Institution claims if the “From Date” is before Dec. 31, 2019. You can submit claims received between April 1, 2018 and December 31, 2019 using either the HICN or the MBI.  If a patient starts getting services in an inpatient hospital, home health, or religious non-medical health care institution before Dec. 31 but stops getting those services after Dec. 31, you may submit a claim using either the HICN or the MBI, even if you submit it after Dec. 31.

Find more information on exceptions here.

More Resources

You can find more information on using the MBI numbers in CMS’ MLN Matters article here

Pennsylvania Medical Society members with questions can also contact our Knowledge Center at 855-PAMED4U (855-726-3348) or  

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