Last reviewed October 6, 2026 by Effective Data's EDI specialists.
When the 270/271 is used, and which way it travels
The 270 typically includes details of the sender, the name of the recipient, information on the plan subscriber, and a description of the eligibility or benefit information requested.
The 271 includes all requested information from the 270 inquiry. Together they are one of the most commonly used EDI document combinations in healthcare, and they are how providers understand a patient's coverage and benefits before treating.
Both documents must be HIPAA-compliant, and both travel either directly between the parties or through a Value-Added Network.
Also called the Eligibility Inquiry, the Eligibility and Benefit Response. Same document, same number.
The segments, and what each one carries
The published X12 structure, minus the segments most partners never use. Each partner's implementation guide narrows this further: which qualifiers, which identifiers, how many decimals. That guide, not the standard, is what your file is validated against.
| Segment | Name | Part | What it carries |
|---|---|---|---|
| ST | Transaction Set Header | Both | Identifies the document as a 270 or 271 and opens the control number the trailer must match. |
| BHT | Beginning of Hierarchical Transaction | Both | Transaction purpose, reference number, date and time. |
| HL | Hierarchical Level | Both | The structure: information source (the payer), information receiver (the provider), subscriber, then dependent. |
| NM1 | Individual or Organizational Name | Both | Each party in the hierarchy, by name and identifier. |
| TRN | Trace | Both | Trace numbers that let the 271 answer be matched to its 270 question. |
| DMG | Demographic Information | Both | The subscriber's birth date and gender, used to identify the member. |
| DTP | Date or Time Period | Both | The date or period of service the inquiry concerns. |
| EQ | Eligibility or Benefit Inquiry | 270 inquiry | What is being asked: the service type codes in question. |
| EB | Eligibility or Benefit Information | 271 response | The answer: coverage, co-insurance, co-payment, deductible and limitations per service type. |
| SE | Transaction Set Trailer | Both | Closes the set. Segment count and control number must match the ST. |
- ST Transaction Set Header Both
- Identifies the document as a 270 or 271 and opens the control number the trailer must match.
- BHT Beginning of Hierarchical Transaction Both
- Transaction purpose, reference number, date and time.
- HL Hierarchical Level Both
- The structure: information source (the payer), information receiver (the provider), subscriber, then dependent.
- NM1 Individual or Organizational Name Both
- Each party in the hierarchy, by name and identifier.
- TRN Trace Both
- Trace numbers that let the 271 answer be matched to its 270 question.
- DMG Demographic Information Both
- The subscriber's birth date and gender, used to identify the member.
- DTP Date or Time Period Both
- The date or period of service the inquiry concerns.
- EQ Eligibility or Benefit Inquiry 270 inquiry
- What is being asked: the service type codes in question.
- EB Eligibility or Benefit Information 271 response
- The answer: coverage, co-insurance, co-payment, deductible and limitations per service type.
- SE Transaction Set Trailer Both
- Closes the set. Segment count and control number must match the ST.
Why yours is being rejected
Every EDI provider publishes what an 270/271 is. What matters in production is why one fails, and these are the failure modes we can put a source against today:
-
A subscriber the payer cannot match. The NM1 and DMG identification has to match the payer's member records; an inquiry with a mis-keyed identifier or birth date returns an error or, worse, the wrong member's answer.
-
Losing the pairing. TRN trace numbers are what tie a 271 back to its 270; a provider system that does not carry them cannot reliably say which question an answer belongs to once volume grows.
If one of these is happening to you right now, skip to the bottom of the page and describe it. Diagnosing rejected documents is most of what we do.
The documents the 270/271 travels with
Frequently asked
+ What is an EDI 270?
The eligibility inquiry, sent by healthcare service providers to insurance agencies or government entities, including Medicare and Medicaid. It typically includes sender details, the recipient, the plan subscriber, and a description of the eligibility or benefit information requested.
+ What is an EDI 271?
The response. A 271 document includes all requested information from the 270 transaction, returning the patient's coverage and benefit detail to the provider.
+ Why do the 270 and 271 matter?
They are one of the most commonly used EDI document combinations in healthcare, and they are how providers understand patients' coverage and benefits. Both must be HIPAA-compliant.
+ How do the 270/271 relate to the 837?
The 270/271 happen before care: they establish what is covered. The 837 happens after: it is the claim for what was done. Checking eligibility first is how providers avoid claims that were never going to be paid.
Is your 270/271 failing, or being mandated by a partner?
Describe the situation and a named EDI specialist will tell you what it takes, including when the answer is that you do not need us.
Or call 847.969.9300Answered by a named EDI specialist on the same business day. If we are not the right answer we will say so on the first call.