US · guidance
CMS Pub. 100-04, ch. 2, § 10.1.1
Changes to Medicare beneficiary identifier
The term Medicare beneficiary identifier (Mbi) is a general term describing a
beneficiary's Medicare identification number. For purposes of this manual, Medicare
beneficiary identifier references both the Health Insurance Claim Number (HICN) and
the Medicare Beneficiary Identifier (MBI) during the new Medicare card transition
period and after for certain business areas that will continue to use the HICN as part of
their processes.
Changes in an individual’s entitlement to Medicare benefits may result in an individual
being assigned a completely different HICN. For example, an individual not entitled to
monthly benefits (000-00-0000T) marries and becomes entitled to wife’s benefits on her
husband’s account (111-11-1111B). If a claim is submitted under the old HICN, the
Common Working File (CWF) disposition code 51 will notify the A/B MAC (A), (B),
(HHH), or DME MAC (whom we will refer to as the MAC when all are meant) of the
new HICN. The MAC will annotate its records and use the new HICN when submitting
future bills or claims.
History
(Rev. 4247, Issued: 03-01-19, Effective: 04-01-19, Implementation: 04-01 -19)
Provenance
- Source
- cms.gov
- Retrieved
- 2026-08-25
- Edition
- iom-2026-08-25
- Content hash
ea8b40ccd831f07683f0e7ceaefc5115062ceb561330fb3f9b1e0eff1e1183e4
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