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An attachment is clinical documentation sent to a payer in support of a claim or predetermination. Common examples include radiographs, periodontal charts, narratives, and intraoral photographs. Much of the current dental workflow relies on proprietary reference numbers because HIPAA did not specify a claims-attachment transaction for decades. Under the standard finalized in 2026, covered entities must support the X12 275 transaction by May 26, 2028.

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Why dental claims need attachments

Dental payers use both the submitted code and supporting evidence to adjudicate major work. The following procedure families commonly require documentation:1 Each payer publishes its own documentation policy by procedure. Maintain a payer-specific list of the CDT codes that require attachments and submit the documentation with the claim when the policy calls for it. Otherwise, the claim may pend while the response deadline continues to run.

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Reference-number workflows

For decades HIPAA had no adopted attachment standard, so the industry used shared repositories and reference numbers carried on claims:
  1. The practice uploads the documentation (radiographs, charting, narrative) to an attachment service’s repository.
  2. The service returns a unique attachment reference number for the attachment set.
  3. The biller places the reference number in the claim’s remarks (or the field the payer’s companion guide designates).
  4. The payer retrieves the attachment from the repository during adjudication.
Common failures include uploading documentation without placing the reference number on the claim and using a repository that the member’s plan does not retrieve from. Not every payer participates with every attachment service, so check the service’s current payer list. Some clearinghouses instead offer an integrated attachment service, so attachments follow the same workflow as the 837D submission without separate repository software. Ask whether claims, attachments, and real-time eligibility share one connection or require separate products.

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The request-for-information cycle

When a payer needs more documentation, it may pend the claim and request information:
  1. The payer suspends adjudication and issues a request, currently by letter, portal message, or a remittance carrying an information-request code. Examples include CARC 252, “an attachment/other documentation is required,” or CARC 16 with a RARC naming the missing element. See CARC codes.
  2. The practice has a response window; miss it and the claim denies for failure to provide requested information.
  3. The response goes back through the payer’s designated channel: an attachment service, portal upload, or mail.
Each request can delay payment. Attach documentation at submission when the payer’s policy requires it, and route new information requests promptly. A predetermination for major work can also identify documentation requirements before treatment. See Get predeterminations. Beginning with the 2028 compliance date, this cycle uses standard transactions: the payer sends an electronic 277 RFAI (Request for Additional Information), and the provider responds with a 275.

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The 2026 final rule

On March 24, 2026, CMS published the HIPAA claims-attachment standard it first proposed in December 2022:2 What it means in practice:
  • Claims-attachment workflows must change. Covered entities must support payer requests through the 277 RFAI and responses through the 275 by May 26, 2028. Existing attachment vendors may preserve a similar upload experience while changing the underlying transaction.
  • Ask vendors for a written implementation plan. If a PMS, clearinghouse, or attachment-vendor contract extends beyond the compliance date, confirm testing dates, fees, contract changes, and support for a transition period.
  • Predetermination and preauthorization attachments are not covered. Those remain subject to payer-specific channels because the final rule did not adopt the proposed prior-authorization attachment standard.

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Sources

  1. Payer documentation demands for crowns, SRP, and implants per payer guidance, for example GEHA, provider attachment instructions. Requirements are payer- and plan-specific; consult each payer’s documentation policy.
  2. Administrative Simplification: Adoption of Standards for Health Care Claims Attachments Transactions and Electronic Signatures, 91 Fed. Reg. 14350 (Mar. 24, 2026). Federal Register; full text (GovInfo); proposed rule: 87 Fed. Reg. 78438 (Dec. 21, 2022), Federal Register.
Last modified on October 11, 2026