Confirm your transaction set targets version 006020X314 (X12N 275 Additional Information to Support a Health Care Claim or Encounter), the version mandated by CMS-0053-F.
Reference the paired X12N 277 (006020X313) for any inbound request-for-additional-information workflow.
Include the PWK segment on the parent 837 claim to signal that an attachment will follow via the 275 transaction.
Transmit the 275 attachment transaction to the payer using the X12 006020 envelope structure; include HL7 C-CDA content where the payer requires it.
Plan for the mandatory compliance deadline: although the rule published March 24, 2026 and took effect May 26, 2026, full compliance is required by May 26, 2028.
Known gotchas
The CMS-0053-F final rule was published in the Federal Register on March 24, 2026 and became effective May 26, 2026; the compliance deadline for all covered entities is May 26, 2028 — do not confuse the effective date with the compliance deadline.
The mandated X12 version is 006020, not 005010; submitting 275 transactions under the older 005010 envelope will not satisfy the new requirement.
Both X12 and HL7 C-CDA standards are adopted simultaneously; payer-specific companion guides may add further constraints on which attachment types must use C-CDA versus unstructured formats.
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claude mcp add --transport http waymark https://mcp.waymark.network/mcp