The Health Insurance Claim Number (HICN) served as the primary identification number for Medicare beneficiaries for decades, used for transactions like billing, eligibility verification, and claims processing. Due to security concerns, the HICN has been largely replaced by a new identifier.
Defining the Health Insurance Claim Number (HICN)
The Health Insurance Claim Number (HICN) was an identifier issued to Medicare beneficiaries by the Social Security Administration or the Railroad Retirement Board. Its structure was directly tied to the beneficiary’s nine-digit Social Security Number (SSN), followed by a one or two-character suffix.
This suffix, known as the Beneficiary Identification Code (BIC), indicated the beneficiary’s relationship to the primary wage earner whose SSN formed the base of the number. For instance, a suffix of “A” indicated the primary wage earner, while a “B” or “B2” might indicate a spouse or second claimant. Because the HICN was printed on the Medicare card, the SSN was easily accessible, creating a security risk.
The HICN was a single, unified identifier necessary for healthcare providers to submit claims for reimbursement from Medicare. It allowed the Centers for Medicare & Medicaid Services (CMS) to track services rendered and process payments accurately. The total length of the HICN could vary, containing up to 11 characters.
The Shift to the Medicare Beneficiary Identifier (MBI)
The fundamental problem with the HICN was its direct connection to the beneficiary’s SSN, which presented a significant security risk. To protect beneficiaries from identity theft and fraud, the Medicare Access and CHIP Reauthorization Act (MACRA) of 2015 mandated the removal of Social Security Numbers from all Medicare cards. This legislative action initiated the Social Security Number Removal Initiative (SSNRI), leading to the creation of the Medicare Beneficiary Identifier (MBI).
The MBI is an 11-character, randomly generated sequence of numbers and uppercase letters designed to replace the SSN-based HICN. This new identifier is considered “non-intelligent,” meaning it does not contain personal identifying information like the beneficiary’s birth date or SSN, making it inherently safer. The Centers for Medicare & Medicaid Services began mailing new Medicare cards with the MBI in April 2018.
The transition period, during which providers could use either the HICN or the MBI for claims submission, ran from April 2018 through December 31, 2019. After this period, the MBI became the required identifier for nearly all Medicare transactions. The MBI uses a specific format that excludes letters like S, L, O, I, and B to prevent confusion with numbers and improve data entry accuracy.
The MBI is unique to each individual beneficiary, unlike the HICN, which sometimes shared an SSN component between a spouse and the primary earner. This shift required CMS to generate approximately 150 million MBIs for both active and archived beneficiaries. The new card design also omitted information like gender and signature, focusing solely on the MBI for identification.
Practical Application: When to Use HICN vs. MBI Today
Today, the Medicare Beneficiary Identifier (MBI) is the standard and required number for all Medicare-related claims, billing, and eligibility checks. The transition period officially ended on January 1, 2020, and claims submitted for services rendered on or after this date must use the MBI or they will be rejected. Beneficiaries should use their new Medicare card, which displays the MBI, for all interactions with healthcare providers.
Despite the mandatory switch, there are a few specific exceptions where the HICN may still be used. The HICN is accepted for certain appeals processes and related forms, and for adjustments within specific internal systems like Drug Data Processing and Risk Adjustment Processing. It may also be used indefinitely for transactions related to the Railroad Retirement Board (RRB) or certain Medicare Secondary Payer (MSP) processes, though CMS returns the MBI on its response.
Beneficiaries who still possess their old Medicare card are advised to shred it to protect their SSN. If a healthcare provider asks for the old HICN, the beneficiary should inform them that the MBI is the correct, current identifier. CMS provided tools to help providers look up a patient’s MBI if they only had the HICN on file, ensuring continuity of care.