HL7 OMP_O09 (Pharmacy/Treatment Order) | Integration Soup HL7 Reference Guide

HL7 OMP_O09 Pharmacy/Treatment Order

A medication or treatment order built around ORC, RXO, RXR, and optional components.

HL7 message structure OMP_O09 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
OMP_O09.PATIENT	Patient group	No	No
PID	Patient Identification	Yes	No
PD1	Patient Additional Demographic	No	No
NTE	Notes and Comments	No	Yes
OMP_O09.PATIENT_VISIT	Patient Visit group	No	No
PV1	Patient Visit	Yes	No
PV2	Patient Visit - Additional Information	No	No
OMP_O09.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
OMP_O09.ORDER	Order group	Yes	Yes
ORC	Common Order	Yes	No
OMP_O09.TIMING	Timing group	No	Yes
TQ1	Timing/Quantity	Yes	No
TQ2	Timing/Quantity Relationship	No	Yes
RXO	Pharmacy/Treatment Order	Yes	No
NTE	Notes and Comments	No	Yes
RXR	Pharmacy/Treatment Route	Yes	Yes
OMP_O09.COMPONENT	Component group	No	Yes
RXC	Pharmacy/Treatment Component Order	Yes	No
NTE	Notes and Comments	No	Yes
OMP_O09.OBSERVATION	Observation group	No	Yes
OBX	Observation/Result	Yes	No
NTE	Notes and Comments	No	Yes
FT1	Financial Transaction	No	Yes
BLG	Billing	No	No

OMP_O09 is a pharmacy/treatment order message. It is used when a placer sends a medication, infusion, compound, or treatment order to a pharmacy or treatment-management system. It is more specific than a generic ORM because the order detail is carried in pharmacy segments.

The order still starts with ORC, because order control is shared across HL7 order workflows. The medication/treatment detail lives in RXO, route in RXR, and compound components in RXC when needed.

A small OMP pharmacy order example

MSH|^~\&|EHR|CITYHOSP|PHARM|CITYHOSP|20260718110000||OMP^O09^OMP_O09|OMP090001|P|2.5.1 PID|1||123456^^^CITYHOSP^MR||Smith^Jane^Anne^^Ms^^L||19800314|F PV1|1|I|WARD5^501^1^CITYHOSP||||12345^Careful^Clara ORC|NW|RX550001^EHR|||||^^^20260718120000|||12345^Careful^Clara TQ1|1|1^dose|QID^Four times daily^HL70335|||20260718120000 RXO|AMOX500^Amoxicillin 500 mg capsule^L|500|mg|PO^Oral^HL70162 RXR|PO^Oral^HL70162 OBX|1|ST|INDICATION^Indication^L||Community acquired pneumonia

What systems do with it

The sender is usually an EHR, CPOE, or medication-management system. The receiver may be an inpatient pharmacy, dispensing system, infusion platform, or integration engine. The receiver evaluates the order, checks medication and route details, and may respond with ORP_O10.

OMP can represent new orders and order changes. As always, ORC-1 drives the action. RXO tells the receiver what is ordered. RXR tells it how the medication or treatment should be given. RXC matters when the order is compound-like.

How to read the structure

The patient and visit group gives the medication order clinical context. The required order group starts with ORC, optional timing, required RXO, notes, required RXR, optional RXC components, optional OBX observations, and finance/billing details.

Use OBX for supporting clinical information such as indication, safety checks, or order questions. Do not use it as a substitute for the structured medication fields the receiver actually maps.

Implementation traps

Medication interfaces are unforgiving. Dose, strength, route, frequency, units, and components must be mapped deliberately. A readable text instruction is not enough if the receiving system makes dispensing or administration decisions from structured fields.

Also agree what system owns changes. A pharmacy may modify, substitute, or reject an order. If the placer ignores pharmacy responses, medication status will drift quickly.

Reference notes

HL7 lists OMP_O09 as the pharmacy/treatment order message. The local v2.5.1 structure shows the ORC, RXO, RXR, RXC, OBX, FT1, and BLG groups used by this order type. See HL7 Europe OMP_O09.