HL7 OMI_O23 (Imaging Order) | Integration Soup HL7 Reference Guide

HL7 OMI_O23 Imaging Order

A clinical order shaped for radiology and imaging workflow.

HL7 message structure OMI_O23 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
SFT	Software Segment	No	Yes
NTE	Notes and Comments	No	Yes
OMI_O23.PATIENT	Patient group	No	No
PID	Patient Identification	Yes	No
PD1	Patient Additional Demographic	No	No
NTE	Notes and Comments	No	Yes
OMI_O23.PATIENT_VISIT	Patient Visit group	No	No
PV1	Patient Visit	Yes	No
PV2	Patient Visit - Additional Information	No	No
OMI_O23.INSURANCE	Insurance group	No	Yes
IN1	Insurance	Yes	No
IN2	Insurance Additional Information	No	No
IN3	Insurance Additional Information, Certification	No	No
GT1	Guarantor	No	No
AL1	Patient Allergy Information	No	Yes
OMI_O23.ORDER	Order group	Yes	Yes
ORC	Common Order	Yes	No
OMI_O23.TIMING	Timing group	No	Yes
TQ1	Timing/Quantity	Yes	No
TQ2	Timing/Quantity Relationship	No	Yes
OBR	Observation Request	Yes	No
NTE	Notes and Comments	No	Yes
CTD	Contact Data	No	No
DG1	Diagnosis	No	Yes
OMI_O23.OBSERVATION	Observation group	No	Yes
OBX	Observation/Result	Yes	No
NTE	Notes and Comments	No	Yes
IPC	Imaging Procedure Control Segment	Yes	Yes

OMI_O23 is the imaging order message. It carries an order from an order placer to an imaging filler such as a RIS, and it can carry enough context for imaging workflow systems to connect the order to studies, procedure steps, devices, and downstream image management.

The practical difference from a generic order is IPC. ORC still says what action is being requested, OBR still carries the ordered procedure, and IPC carries imaging procedure control identifiers that help the imaging department align order, accession, study, and procedure-step context.

A small OMI imaging order example

MSH|^~\&|EHR|CITYHOSP|RIS|CITYHOSP|20260718101500||OMI^O23^OMI_O23|OMI230001|P|2.5.1 PID|1||123456^^^CITYHOSP^MR||Smith^Jane^Anne^^Ms^^L||19800314|F PV1|1|O|ED^IMAGING^^CITYHOSP||||12345^Careful^Clara ORC|NW|IMG440001^EHR|||||^^^20260718110000|||12345^Careful^Clara OBR|1|IMG440001^EHR||CTHEAD^CT Head without contrast^L|||20260718110000|||||||||12345^Careful^Clara IPC|ACC20260718001|STUDY20260718001|PROC20260718001|STEP20260718001|CTROOM1

What systems do with it

The placer sends the order to a RIS or imaging department information system. The filler schedules, protocolizes, performs, or manages the requested imaging service. PACS and image-management systems may need the same identifiers to keep images, studies, procedure steps, reports, and order updates in the same lane.

Supporting observations in OBX may carry clinical indications, pregnancy status, contrast questions, or safety notes. Those are order details, not final imaging results.

How to read the structure

The patient and visit groups look like other order messages. The required order group starts with ORC, timing, and OBR. IPC is required and can repeat, because an imaging order may be split into procedures or steps that downstream imaging systems must distinguish.

For production work, decide which identifier is authoritative for accession, study, requested procedure, and scheduled step. If the same value is copied everywhere, the message may pass basic validation while still being useless to a PACS workflow.

Implementation traps

The common trap is flattening imaging into a normal OBR-only order and losing the imaging identifiers. That can leave the RIS, modality worklist, PACS, and reporting system talking about related but unlinked objects.

Another trap is filing imaging order updates like reports. OMI manages the request. The report usually travels later as ORU_R01, MDM_T02, or another local reporting pattern.

Reference notes

HL7's OMI_O23 description highlights RIS/PACS-style imaging department workflows and the role of IPC in sharing imaging study and procedure-step context. See HL7 Europe OMI_O23.