Medicare HIC Number & MBI: Completing Box 1a on the CMS-1500 Form
Understanding and accurately entering patient identification is paramount for successful claim processing on the CMS-1500 form. Specifically, Box 1a, designated for the insured’s identification number, is a critical field that directly impacts whether a claim is accepted or denied. This guide will walk you through the evolution of Medicare patient identifiers, from the traditional Health Insurance Claim (HIC) Number to the current Medicare Beneficiary Identifier (MBI), ensuring your Medicare billing practices are compliant and efficient.
The HICN to MBI Transition: A Critical Update for Medicare Billing
The Centers for Medicare & Medicaid Services (CMS) initiated a crucial transition from the Health Insurance Claim Number (HICN) to the new Medicare Beneficiary Identifier (MBI) to protect beneficiaries from identity theft. This phased rollout, which began in April 2018 and concluded in January 2020, mandated the use of MBIs for all new Medicare fee-for-service claims.
While MBIs are now the standard, there are very limited circumstances where HICNs may still be used, such as for certain appeals, adjustments to claims originally submitted with an HICN, or during the transition period if CMS allowed it for specific scenarios. For all new claims, providers must use the MBI.
Historical Context: The Health Insurance Claim (HIC) Number
For decades, the HIC number served as the primary identifier for Medicare beneficiaries. These numbers were tied to the Social Security number of the primary wage earner, followed by a unique suffix. While these numbers are largely obsolete for new claims, understanding their structure provides historical context for older records and specific adjustment scenarios.
Traditional HIC numbers consisted of nine digits (representing the Social Security number of the insured) followed by a valid suffix. When entering an HIC number, it was crucial to include the complete number exactly as it appeared on the patient’s Medicare card, without spaces or hyphens.
Understanding HIC Number Suffixes
The suffix appended to a HIC number indicated the beneficiary’s relationship to the primary wage earner. These suffixes are unique to HICNs and are not part of the MBI. Here is a breakdown of common HIC number suffixes:
| Code | Type and Explanation |
|---|---|
| A | Wage earner (retirement): Indicates the beneficiary is the primary wage earner receiving retirement benefits. |
| B | Wife: Denotes the beneficiary is the wife of a retired wage earner. |
| B1 | Husband: Denotes the beneficiary is the husband of a retired wage earner. |
| C1-C9 | Child: Indicates a child of a retired wage earner (includes disabled or student child). |
| D | Aged widow: Refers to an aged widow of a deceased wage earner. |
| D1 | Widower: Refers to an aged widower of a deceased wage earner. |
| E1 | Surviving divorced mother: Indicates a surviving divorced mother of a deceased wage earner. |
| E5 | Surviving divorced father: Indicates a surviving divorced father of a deceased wage earner. |
| G | Claimant of lump-sum death benefits: For individuals claiming a lump-sum death benefit. |
| M | Uninsured – premium health insurance benefits (Part A): For those uninsured but paying premiums for Part A. |
| M1 | Uninsured – qualified for but refused HIB (Part A): For those who qualified for but refused Hospital Insurance Benefits (Part A). |
| T | Uninsured – entitled to HIB (Part A) under deemed or renal provisions: For those entitled to Part A under special provisions, such as End-Stage Renal Disease (ESRD). |
| W | Disabled widow: A disabled widow of a deceased wage earner. |
| W1 | Disabled widower: A disabled widower of a deceased wage earner. |
Current Standard: The Medicare Beneficiary Identifier (MBI)
The Medicare Beneficiary Identifier (MBI) is the new, unique, 11-character alphanumeric identifier for Medicare beneficiaries. Unlike the HICN, the MBI is not based on the beneficiary’s Social Security number, offering enhanced protection against identity fraud. Understanding the Medicare ID format changes is crucial for accurate claim submission.
MBI Format and Where to Find It
- Format: The MBI is an 11-character alphanumeric identifier. It follows a specific pattern: Character 1 is always a number (0-9), character 2 is always a letter (A-Z), character 3 is always a number (0-9), character 4 is always a letter (A-Z), character 5 is always a number (0-9), character 6 is always a letter (A-Z), character 7 is always a number (0-9), character 8 is always a letter (A-Z), character 9 is always a number (0-9), character 10 is always a letter (A-Z), and character 11 is always a number (0-9). The letters S, L, O, I, B, and Z are never used to avoid confusion with numbers.
- Location: Beneficiaries receive their MBI on their new Medicare card. Providers can also obtain a patient’s MBI through the Medicare Administrative Contractor (MAC) portal if they have a valid HICN for the patient, or by asking the patient to present their new Medicare card.
Guidelines for Entering the MBI in Box 1a of the CMS-1500
When completing Box 1a on the CMS-1500 claim form or submitting electronic claims, enter the patient’s MBI exactly as it appears on their Medicare card. Crucially, do not include any spaces or hyphens when entering the MBI. Accuracy in this field is vital for proper Medicare claim processing and avoiding denials related to incorrect beneficiary identification.
Ensuring Accuracy for Seamless Medicare Claims Processing
In summary, for current Medicare billing, the Medicare Beneficiary Identifier (MBI) is the required patient identification for Box 1a on the CMS-1500 form. Providers must ensure they are using the MBI for new claims to comply with CMS guidelines and facilitate efficient payment. For official MBI guidelines and the latest updates, always refer to the official CMS New Medicare Card website. Staying informed about these updates helps streamline your Medicare billing and claim form submission.