HL7 ORR_O02 Order Response

The classic application response to an ORM order.
HL7 message structure ORR_O02 groups and segments from HL7 v2.5.1 Hide structure

These are the generated groups and segments for the version selected at the top of the page. The article explains the workflow, and this panel follows the chosen HL7 version.

Message Structure

SegmentNameRequiredRepeatable
MSH
 Message Header Yes No
MSA
 Message Acknowledgment Yes No
ERR
 Error No Yes
NTE
 Notes and Comments No Yes
ORR_O02.RESPONSE
 Response group No No
ORR_O02.PATIENT
 Patient group No No
PID
 Patient Identification Yes No
NTE
 Notes and Comments No Yes
ORR_O02.ORDER
 Order group Yes Yes
ORC
 Common Order Yes No
ORR_O02.OBRRQDRQ1RXOODSODT_SUPPGRP
 Obrrqdrq1rxoodsodt Suppgrp group Yes No
NTE
 Notes and Comments No Yes
CTI
 Clinical Trial Identification No Yes

ORR_O02 is the traditional order response to an ORM_O01 order message. It is more than a transport ACK. It can tell the placer whether the filler accepted the order and can return the filler order number or order-level state that later updates and results will need.

In older interfaces, ORR is the response pattern people reach for when a normal ACK is too thin. A basic ACK can say "I received the message." ORR can say "I accepted this order, here is the filler number, and here is the order detail I am acknowledging."

A small ORR response example

MSH|^~\&|LAB|CITYLAB|EHR|CITYHOSP|20260718105003||ORR^O02^ORR_O02|ORR020001|P|2.5.1 MSA|AA|ORM00001 PID|1||123456^^^CITYHOSP^MR||Smith^Jane^Anne^^Ms^^L ORC|OK|ORD448811^EHR|LAB998811^LAB||||||20260718105003 OBR|1|ORD448811^EHR|LAB998811^LAB|718-7^Hemoglobin^LN

What systems do with it

The filler sends ORR_O02 after processing an ORM order. The placer uses it to mark the order accepted or rejected, store filler identifiers, and decide whether follow-up actions are needed. ERR and NTE can explain failures or warnings.

The most important segment after MSA is usually ORC. ORC-1 carries the order control response such as accepted, unable to accept, cancelled as requested, or another agreed value. ORC-2 and ORC-3 tie the placer and filler order identifiers together.

How to read the structure

The message starts with MSH, MSA, optional ERR, and optional notes. The response group can contain patient identity and repeating order groups. The local v2.5.1 structure preserves the older order-response family that also overlaps with pharmacy acknowledgment variants.

If an order detail is present, make sure the identifiers in ORC and the detail segment agree. That rule is boring until it is broken, and then every update and result starts matching badly.

Implementation traps

Do not substitute ORR for ACK without agreeing on the workflow. Some senders expect a basic ACK immediately and an order response later. Others expect ORR on the same two-way exchange. That affects timeouts, retries, and user feedback.

Also avoid treating MSA-1 AA as order acceptance. The order outcome belongs in ORC and, when there is a problem, ERR.

Reference notes

Caristix describes ORR_O02 as the application acknowledgment response to ORM. The HL7AU ordering notes describe ORR as a general order acknowledgment and explain why ORC is mandatory when order detail is present. See Caristix ORR_O02 and HL7AU observation ordering.