HL7 RER_RER Pharmacy/Treatment Encoded Order Information

The old-style query response for pharmacy's encoded view of an order.
HL7 message structure RER_RER 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
SFT
 Software Segment No Yes
RER_RER.DEFINITION
 Definition group Yes Yes
QRD
 Original-Style Query Definition Yes No
QRF
 Original style query filter No No
RER_RER.PATIENT
 Patient group No No
PID
 Patient Identification Yes No
NTE
 Notes and Comments No Yes
RER_RER.ORDER
 Order group Yes Yes
ORC
 Common Order Yes No
RXE
 Pharmacy/Treatment Encoded Order Yes No
RXR
 Pharmacy/Treatment Route Yes Yes
RXC
 Pharmacy/Treatment Component Order No Yes
DSC
 Continuation Pointer No No

RER_RER returns pharmacy or treatment encoded order information in response to an original-style query. It is the pull-style response for the pharmacy interpretation of an order, similar in content to what encoded-order workflows such as RDE_O11 carry as events.

Use it when a system needs to ask, "how did pharmacy encode this order?" rather than "what was prescribed?" or "what was dispensed?"

A small RER RER example

MSH|^~\&|PHARMACY|CITYHOSP|EHR|CITYHOSP|20260723132000||RER^RER^RER_RER|RER00001|P|2.5.1 MSA|AA|QRYRER001 QRD|20260723131900|R|I|QRYRER001|||1^RD|123456^^^CITYHOSP^MR|RXE^Encoded order query^L|PHARMACY|T PID|1||123456^^^CITYHOSP^MR||Rivera^Maya^^^^^L||19750519|F ORC|RE|ORD448811^EHR|RX990201^PHARMACY|GRP448811|CM RXE||AMOX500^Amoxicillin 500 mg capsule^L|500||mg^milligram^UCUM|CAP^Capsule^L|TAKE WITH FOOD^Take with food^L RXR|PO^Oral^HL70162 RXC|A^Additive^HL70166|CLAV125^Clavulanate 125 mg^L|125|mg^milligram^UCUM

What workflow it represents

The requester wants the pharmacy/treatment application's encoded order view. That usually means the product, dose, units, route choices, component detail, and pharmacy-specific instructions after the order has been interpreted by the filling system.

This is useful for reconciliation and display, but it can be risky if the receiver treats it as a new order event.

How to read the structure

The response envelope starts with MSH, MSA, optional ERR, and optional SFT.

Each DEFINITION group contains required QRD, optional QRF, optional patient context, and repeating ORDER groups.

Each ORDER group uses ORC for order identity and status, required RXE for encoded order details, repeating RXR for routes, and optional RXC for compound or component detail.

Implementation traps

Do not confuse RXO and RXE. RXO is the requested order; RXE is the pharmacy/treatment application's encoded order. That difference is exactly why RER_RER exists.

Pay close attention to timing. Pharmacy may encode dispense or give schedules differently from the original requested timing, and receivers need to know which one they are displaying.

Component rows are another common pain point. If RXC appears, preserve the component type, code, amount, and units together.

Reference notes

HL7 v2.5.1 query listings identify RER_RER as pharmacy/treatment encoded order information. The local structure returns QRD/QRF query context with ORC, RXE, RXR, and RXC order detail.