The full table
The ones you touch daily
Two dental details matter in this flow. A predetermination is not a separate transaction: the 837D itself can be sent as a predetermination request, and the estimate returns without payment. The information-request loop currently uses a mix of letters, portals, and proprietary attachment services. The 277 RFAI and 275 pair will standardize that exchange on the compliance schedule described below.Acknowledgment hierarchy
Three responses can come back after you submit an 837D, and they mean different things.
A 277CA rejection is not a denial. Nothing was adjudicated and no determination was made, so there is nothing to appeal. Correct the data and resubmit as a new claim, not as a corrected claim, because there is no original claim in the payer’s system to correct.
A denial, by contrast, appears in the 835 as a $0 or reduced payment with a denial CARC and may carry appeal rights. In dental billing, first determine whether the line is a true denial, a downgrade, or a frequency limitation. The latter two may reflect benefit design rather than an appealable determination. See Claim denials.
Versions
Most healthcare transactions currently use the 5010 implementation guides adopted under HIPAA administrative simplification.1 Version identifiers appear in theGS08 element and the ST03 element; 005010X224A2 for the 837D, 005010X222A1 for the 837P.
You will see these strings in error messages. They identify which implementation guide the file claims to follow.
The exception is the newly adopted attachments pair, which arrives at version 6020: the 275 as 006020X314 and the 277 RFAI as 006020X313.2
The attachments pair: 275 and 277 RFAI
Dental claims frequently require attachments for crowns, SRP, implants, and other services. In the absence of an adopted standard, the industry developed proprietary repositories and NEA-number workflows. The March 2026 final rule (91 Fed. Reg. 14350) adds the 275 (attachment transmission) and 277 RFAI (payer request for information) to the standard set, with a compliance date of May 26, 2028.2 Proprietary and standard workflows may coexist during the transition. See Dental attachments for what the rule adopted and omitted.Companion guides
The X12 implementation guide defines required, situational, and optional elements. Payers publish companion guides specifying how they interpret the situational and optional parts, what identifiers they expect, how they want files delivered, and what their front-end edits check. Delta Dental publishes one; UnitedHealthcare publishes a separate one for its dental line; every Medicaid dental benefit administrator has its own. Two payers can follow the same X12 standard while applying different situational requirements and front-end edits. A clearinghouse helps manage that payer-specific variation. See What is a clearinghouse?.Where each transaction shows up
Automation opportunities
For a multi-location group, these transactions support several useful forms of automation:
This work requires programmatic access to the transactions, so include it in clearinghouse selection as well as PMS evaluation. Some clearinghouses expose both JSON and X12 interfaces, while others rely on batch file exchange. See Choose a clearinghouse.
PHI
837D, 835, 271, and 277 files all contain protected health information: names, member IDs, dates of service, procedure detail, and attachments are clinical records outright. Encrypt in transit and at rest, access-control them, and cover any analytics store in your BAAs and your security risk analysis. See HIPAA fundamentals.Sources
- HIPAA administrative simplification, 45 C.F.R. pts. 160, 162. CMS, Administrative Simplification: Transactions. Standards maintained by ASC X12.
- Administrative Simplification: Adoption of Standards for Health Care Claims Attachments Transactions and Electronic Signatures, 91 Fed. Reg. 14350 (Mar. 24, 2026), adopting X12N 275 (006020X314) and X12N 277 RFAI (006020X313), compliance May 26, 2028. Federal Register.