Medicare Beneficiary Identifier (MBI)

Beneficiaries Receiving New Medicare Numbers to Replace Lost or Stolen Card

When a beneficiary reports their Medicare card lost or stolen, they will receive a new Medicare Beneficiary Identifier (MBI) number. When a beneficiary receives a new MBI number, suppliers must immediately switch to billing with the new MBI. Billing with the old MBI may result in receiving denials with Reason Code 16, Remark Codes MA27 N382.

  • Reason Code 16 - Claim/service lacks information or has submission/billing error(s).
  • Remark Code: MA27 and - Missing/incomplete/invalid entitlement number or name shown on the claim
  • Remark Code: N382 - Missing/incomplete/invalid patient identifier

If you receive a denial with the above reason and remark codes, please verify the patient's MBI using the NMP MBI Lookup Tool.

Please follow the instructions on the Denial Code Resolution tool for this reason and remark code denial.

Medicare Beneficiary Identifier (MBI)

The Medicare Access and CHIP Reauthorization Act of 2015 (MACRA) required CMS to remove Social Security Numbers (SSNs) from all Medicare cards by April 2019. A new randomly generated Medicare Beneficiary Identifier (MBI) replaced the SSN-based Health Insurance Claim Number on new Medicare cards for transactions like billing, eligibility status, and claim status.

Implementation: January 1, 2020

Regardless of date of service, providers must use the MBI for all Medicare transactions.

  • Use MBI as soon as your beneficiary receive their new card
  • MBI is effective once new card is received
  • New Medicare beneficiaries will only be assigned an MBI

Claims not submitted with the MBI as of January 1, 2020 will be rejected and will need to be resubmitted with a valid MBI.

A beneficiary's MBI may change if their card was lost or stolen. In these instances, the provider will need to obtain the new MBI from the beneficiary or through the Noridian Medicare Portal.

  • Claim status query - If checking status of a claim with a date of service on/after January 1, 2020, MBI must be used

MBI Format

  • MBI is randomly generated
  • MBI consists of 11 non-intelligent characters (number and upper-case letters) and have no special meaning
    • Numbers 1-9 and all letters from A-Z, except for S, L, O, I, B, and Z
  • MBI Example: 1EG4-TE5-MK73
Position 1 2 3 4 5 6 7 8 9 10 11
Type C A AN N A AN N A A N N


C - Numeric 1 thru 9 N - Numeric 0 thru 9 AN - Either A or N A - Alphabetic Character (A...Z); Excluding (S, L, O, I, B, Z)

  • Position 1 - numeric values 1 thru 9
  • Position 2 - alphabetic values A thru Z (minus S, L, O, I, B, Z)
  • Position 3 - alpha-numeric values 0 thru 9 and A thru Z (minus S, L, O, I, B, Z)
  • Position 4 - numeric values 0 thru 9
  • Position 5 - alphabetic values A thru Z (minus S, L, O, I, B, Z)
  • Position 6 - alpha-numeric values 0 thru 9 and A thru Z (minus S, L, O, I, B, Z)
  • Position 7 - numeric values 0 thru 9
  • Position 8 - alphabetic values A thru Z (minus S, L, O, I, B, Z)
  • Position 9 - alphabetic values A thru Z (minus S, L, O, I, B, Z)
  • Position 10 - numeric values 0 thru 9
  • Position 11 - numeric values 0 thru 9

MBIs will fit on claim forms same as a HICN. No spaces or dashes.

Each Medicare beneficiary will receive an MBI.

How to Prepare

  1. Beneficiary Intake
    • At time of service, ask beneficiaries if he/she has a new Medicare card
    • Verify beneficiary's address
      • He/she won't get a new card if their address is incorrect
      • If address on file is different than address in eligibility response, ask your beneficiary to contact Social Security Administration (SSA) at 1-800-772-1213 to update their records

Eligibility Transaction Responses

Providers can use the Noridian Medicare Portal (NMP) as a Look-up Tool for MBIs. To receive the MBI from NMP, the beneficiary must give a provider his/her HICN plus verify their first name, last name, and date of birth. Beneficiaries can also log into to obtain their MBI.


Last Updated Jan 31 , 2024

Related Articles

paginationType noridian
Articles Source Posted
When to Use the MBI 12/12/2019