EDI 276 and EDI 277 (ASC X12N 005010X212): Health Care Claim Status Request, Response, STC Codes & 277CA Explained

EDI 277 (Health Care Claim Status Response) and its paired inquiry transaction EDI 276 (Health Care Claim Status Request) are the federally mandated ASC X12N Version 5010 electronic data interchange standards used by healthcare providers, medical claims clearinghouses, and health plans to track the adjudication status of submitted medical claims. Governed under HIPAA Administrative Simplification at 45 CFR § 162.1402, the 276/277 transaction pair automates accounts receivable follow-up without manual payer portal lookups or telephone inquiries.

What Is EDI 277?

Within the EDI in healthcare lifecycle, an EDI 277 message is an electronic transmission returned by a health plan or clearinghouse that reports the current processing stage of a previously submitted EDI 837P or 837I claim. In operational revenue cycle management, healthcare IT teams encounter two distinct ASC X12N Version 5010 Technical Report Type 3 (TR3) implementations of the 277 transaction:

• Solicited EDI 277 Claim Status Response (005010X212): Transmitted in direct response to a provider-initiated EDI 276 (005010X212) inquiry. It reports whether a claim is pending adjudication, suspended for medical review, rejected for missing data, or finalized for payment (https://x12.org/products/technical-reports).
• Unsolicited EDI 277CA Health Care Claim Acknowledgment (005010X214): Sent automatically by a clearinghouse or payer immediately after ingesting an EDI 837 batch—without waiting for an EDI 276 request—to confirm front-end pre-adjudication acceptance or rejection at the claim level.

Transaction Code	ASC X12N TR3 ID	Direction	Trigger Mechanism & Function
EDI 276	005010X212	Provider / HIS → Payer	Solicited inquiry requesting the status of one or more submitted claims by date of service, patient, and charge amount.
EDI 277	005010X212	Payer → Provider / HIS	Solicited response returning adjudication status via STC segments for each queried claim or service line.
EDI 277CA	005010X214	Payer / Clearinghouse → Provider	Unsolicited front-end claim acknowledgment reporting whether each claim passed WEDI SNIP pre-adjudication edits.
EDI 277RFAI	005010X213	Payer → Provider	Request for Additional Information soliciting clinical attachments (e.g., operative notes or medical records) needed to adjudicate a pended claim.

Hierarchical Loop Structure and the STC Segment

Both the EDI 276 request and the EDI 277 response organize transaction participants into four nested Hierarchical Level (HL) loops:

1. Loop 2000A — Information Source Level: Identifies the health plan, Medicare Administrative Contractor (MAC), or clearinghouse answering the status inquiry (NM1*PR).
2. Loop 2000B — Information Receiver Level: Identifies the billing organization or hospital system submitting the inquiry (NM1*41).
3. Loop 2000C — Service Provider Level: Identifies the rendering or billing healthcare provider (NM1*1P) using their 10-digit National Provider Identifier (NPI).
4. Loop 2000D / 2000E — Subscriber and Dependent Level: Identifies the insured member (NM1*IL) and, if applicable, the dependent patient (NM1*QC), followed by Loop 2200D/2200E (Claim Status Tracking Number TRN) and optional Loop 2220D/2220E (Service Line Information SVC).

Anatomy of the STC (Status Information) Segment

The core payload of an EDI 277 response resides in the STC (Status Information) segment within Loop 2200D (claim level) or Loop 2220D (service line level). The composite element STC01 combines up to three external Washington Publishing Company (WPC) / X12 code lists separated by sub-element delimiters:

• STC01-1 — Health Care Claim Status Category Code (Code Source 507): Broadly classifies the lifecycle state, such as A0 (Acknowledgement/Forwarded), A1 (Acknowledgement/Receipt), A2 (Acknowledgement/Acceptance into adjudication system), A3 (Acknowledgement/Returned as unprocessable), P0–P5 (Pending), F0–F4 (Finalized/Paid/Denied), or R0–R16 (Requests for additional information).
• STC01-2 — Health Care Claim Status Code (Code Source 508): Provides the granular reason (for example, 20 for “Entity’s National Provider Identifier [NPI] not on file” or 35 for “Claim/Encounter not found”).
• STC01-3 — Entity Identifier Code: Indicates which party the status code applies to (such as PR for Payer, 85 for Billing Provider, or IL for Insured/Subscriber).

HL*4*3*22*0~
DMG*D8*19680415*F~
NM1*IL*1*DOE*JANE****MI*987654321~
TRN*2*CLM2026110901~
STC*F1:65:PR*20261109*WQ*1450.00*920.00*20261108**20261108*CHK884920~
REF*1K*88392019283~
DTP*472*D8*20261028~

How Is EDI 277 Used in Clinical Research and Healthcare?

In hospital revenue cycle operations and clinical trial billing compliance, automated EDI 276/277 workflows prevent timely-filing write-offs and isolate research-related claim holds:

• CAQH CORE 250 Real-Time Operating Rules: Under the federally mandated CAQH CORE 250 Claim Status Rule (45 CFR § 162.1403), HIPAA-covered health plans must return a real-time EDI 277 response within 20 seconds or less for at least 86% of inquiries, and batch 276 submissions received by 9:00 p.m. Eastern Time must have a 277 response available by 7:00 a.m. Eastern Time within two business days.
• Front-End Rejection Resolution via 277CA: Unlike post-adjudication denials reported on an EDI 835 Electronic Remittance Advice (which enter formal denial management and appeals), a 277CA rejection with Category Code A3 or A7 means the payer never accepted the claim into adjudication. Billing scrubbers parse 277CA responses daily so coders can correct syntax or NPI errors and resubmit before timely-filing deadlines expire.
• Clinical Trial Qualifying Claim Tracking: When academic medical centers submit routine-care clinical trial claims carrying Condition Code 30, ICD-10-CM Z00.6, and the 8-digit NCT number, automated 276/277 polling monitors whether Medicare Advantage or commercial payers pend the claim (STC01-1 = P2) for clinical trial protocol verification.

Frequently Asked Questions

What is EDI 277?

EDI 277 is the HIPAA-mandated ASC X12N Health Care Claim Status Response transaction (005010X212) sent by a health plan or clearinghouse to report whether a submitted medical claim has been received, accepted, pended, rejected, or finalized for payment or denial.

How is EDI 277 used in clinical research and healthcare?

Healthcare providers and clinical research billing teams use automated EDI 276 inquiries and EDI 277/277CA responses to verify front-end claim acceptance, detect unprocessable claims (A3/A7 status categories) before timely-filing windows close, and monitor pended routine-care clinical trial claims.