HL7 ORG_O20 (General Clinical Order Response) | Integration Soup HL7 Reference Guide

HL7 ORG_O20 General Clinical Order Response

The filler answers an OMG order with acceptance, rejection, or useful order state.

HL7 message structure ORG_O20 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

Segment	Name	Required	Repeatable
MSH	Message Header	Yes	No
MSA	Message Acknowledgment	Yes	No
ERR	Error	No	Yes
SFT	Software Segment	No	Yes
NTE	Notes and Comments	No	Yes
ORG_O20.RESPONSE	Response group	No	No
ORG_O20.PATIENT	Patient group	No	No
PID	Patient Identification	Yes	No
NTE	Notes and Comments	No	Yes
ORG_O20.ORDER	Order group	Yes	Yes
ORC	Common Order	Yes	No
ORG_O20.TIMING	Timing group	No	Yes
TQ1	Timing/Quantity	Yes	No
TQ2	Timing/Quantity Relationship	No	Yes
OBR	Observation Request	No	No
NTE	Notes and Comments	No	Yes
CTI	Clinical Trial Identification	No	Yes
ORG_O20.SPECIMEN	Specimen group	No	Yes
SPM	Specimen	Yes	No
SAC	Specimen Container detail	No	Yes

ORG_O20 is the application response to an OMG_O19 general clinical order. It is where the filler says whether it accepted the order message and, when useful, echoes the patient and order details with the filler identifiers or order status that the placer needs next.

Like other order responses, ORG has two layers of meaning. MSA says whether the incoming message was accepted at the application level. ORC says what happened to the order itself.

A small ORG response example

MSH|^~\&|CARDIO|CITYHOSP|EHR|CITYHOSP|20260718100003||ORG^O20^ORG_O20|ORG200001|P|2.5.1 MSA|AA|OMG190001 PID|1||123456^^^CITYHOSP^MR||Smith^Jane^Anne^^Ms^^L ORC|OK|ORD550001^EHR|FILL770001^CARDIO||||||20260718100003 OBR|1|ORD550001^EHR|FILL770001^CARDIO|ECG12^12 lead ECG^L|||20260718103000

What systems do with it

The filler sends ORG_O20 back to the placer or integration engine after evaluating the OMG order. A clean response may include only MSH and MSA. A more useful response includes ORC and OBR so the placer can store the filler order number, current order status, scheduled time, or reason for rejection.

ERR matters when the order is rejected. A good ERR tells the sender whether the problem is syntax, missing order detail, unsupported order control, invalid service code, wrong patient, or a business rule.

How to read the structure

The response group is optional, which is why some valid ORG messages are short. When the response includes an OBR, ORC is required in the order group. That ORC is the practical anchor for order state, filler identifiers, and the outcome of ORC-1.

Do not confuse MSA-1 with ORC-1. AA can mean the message was processed, while ORC can still say the order was unable to be cancelled, rejected, or changed differently than requested.

Implementation traps

If the filler assigns an order number, send it back consistently. Many order integrations only become stable after the placer stores both the placer and filler identifiers.

Also avoid vague rejects. If the order failed because the service code is not orderable, because the patient location is invalid, or because the requested timing is impossible, put that in ERR or NTE instead of leaving support staff to infer it from a generic MSA value.

Reference notes

HL7 describes ORG_O20 as the application acknowledgment to an OMG message and notes that ORC is required when OBR is present. See HL7 Europe ORG_O20.