X12 270/271 Eligibility Inquiry and Response: A Practical Guide
How the HIPAA X12 270/271 pair works together to verify patient insurance eligibility in real time, with the segment structure and benefit codes that matter most.
In this article
Few HIPAA transactions have as much day-to-day operational impact as the 270/271 pair. Every time a front-desk system checks 'is this patient covered,' it's almost certainly firing a 270 and parsing a 271 behind the scenes. Getting this pair right — and understanding its benefit codes — directly affects claim denial rates.
1. Why eligibility checks matter
Eligibility verification catches coverage problems before a service is rendered, rather than after a claim is denied weeks later. It also surfaces patient financial responsibility (copay, deductible) so front-desk staff can collect accurately at time of service.
2. The 270 request
A 270 is built as a hierarchy: Information Source (the payer) → Information Receiver (the provider) → Subscriber (the patient). The EQ segment specifies which service type category is being asked about, using standardized codes like 30 (Health Benefit Plan Coverage) or 88 (Pharmacy).
ST
This is an envelope or control segment. Select a highlighted segment on the left (shown in green) for a full business explanation.
3. The 271 response
The 271 mirrors the same hierarchy and answers with one or more EB (Eligibility or Benefit Information) segments — one to confirm overall active/inactive status, and additional ones for specific benefit values like copay or coinsurance percentage.
ST
This is an envelope or control segment. Select a highlighted segment on the left (shown in green) for a full business explanation.
4. Understanding EB codes
| EB01 Code | Meaning |
|---|---|
| 1 | Active Coverage |
| 6 | Inactive |
| B | Co-Payment |
| A | Co-Insurance |
| C | Deductible |
5. Example transactions
Below is a realistic pair: a provider asking about a patient's general health coverage, and the payer confirming active coverage with a $30 copay.
HL*3*2*22*0~
NM1*IL*1*DOE*JANE****MI*W123456789~
DMG*D8*19850612*F~
EQ*30~EB*1**30**Gold PPO Plan~
EB*B**30**Gold PPO Plan*27*30~6. Real-time vs. batch processing
Most payers support real-time 270/271 exchange with a response expected within 20-30 seconds, which is what powers point-of-service eligibility checks. Some smaller or legacy payer systems still only support batch processing, returning 271 responses within a scheduled window (often overnight), which requires a different workflow — verification the day before rather than at check-in.
7. How the 270/271 flow works
The diagram below shows the complete round trip: how a front-desk check-in becomes a 270 inquiry, travels through a clearinghouse to the payer, and returns as a 271 with coverage detail — usually in well under a minute. Press Play Flow to watch it travel, or click a step for detail.
How it works
How 270 Eligibility Inquiry Works
Sender
Provider / Clearinghouse
Receiver
Payer / Health Plan
Direction
Provider → Payer
Standard
ANSI ASC X12
Version
005010X279A1
Transport
AS2 / SFTP / API / Clearinghouse
Business Purpose
Healthcare
Sender — Provider / Clearinghouse
EDI Transmission
270
Eligibility, Coverage or Benefit Inquiry
ANSI ASC X12 005010X279A1
Receiver — Payer / Health Plan
Related transaction flows
Need help understanding this EDI flow?
Ask EDI AI →270 Eligibility Inquiry workflow. Steps: Patient Check-In, Generate 270 Inquiry, Send via Clearinghouse, Payer Receives Inquiry, Member Lookup, Return 271 Response. Transmitted from Provider / Clearinghouse to Payer / Health Plan via AS2, SFTP, API, Clearinghouse, following ANSI ASC X12 005010X279A1.
8. Common errors
| Error | Likely Cause | Fix |
|---|---|---|
| 271 returns 'Subscriber Not Found' | Member ID has extra formatting not present at the payer | Strip formatting before submission |
| Real-time inquiry times out | 270 sent without a required EQ01 service type code | Always populate EQ01 explicitly |
| Front desk sees coverage but no copay | Payer only returns general active-coverage EB, not benefit-specific EB | Confirm payer supports service-type-specific benefit detail |
Related transactions
Eligibility, Coverage or Benefit Inquiry
The HIPAA X12 270 is a request from a healthcare provider to a payer asking whether a patient has active insurance coverage and what benefits apply.
Eligibility, Coverage or Benefit Information
The HIPAA X12 271 is the payer's response to a 270 inquiry, detailing whether the patient is covered and describing plan benefits, copays, and limitations.
Health Care Claim Status Request
The HIPAA X12 276 asks a payer for the current processing status of a previously submitted health care claim.
Health Care Claim Status Response
The HIPAA X12 277 is the payer's answer to a 276, reporting where a claim stands in adjudication.
Frequently asked questions
In most high-volume practices, yes — typically run at scheduling or check-in.
Have a follow-up question about this topic?
Ask EDI AI →