HL7 ORS Messages: Stock Requisition Response

HL7 ORS messages acknowledge or respond to a stock requisition order (OMS). An ORS message is sent from the materials management or central supply inventory system back to the originating care unit or clinical department to confirm that the requested stock items (such as standard clinical supplies, gloves, or bandages) have been accepted, rejected, or updated with fulfilment details (like filled quantities or out-of-stock notices). This page explains what an ORS message represents, the trigger event that carries it, every segment the message can contain and what each one holds, and how an ORS response relates to FHIR. Sample content is constructed for illustration with fictional identifiers.

What an ORS message represents

An ORS message — ORS stands for Stock Requisition Response — communicates a supply system's response to a standard inventory request. The core of the message is the MSA segment, which provides the transaction-level acknowledgement (such as AA for accepted or AE for error), and one or more repeating ORDER groups containing an echoed RQD segment to identify the specific requisitioned stock items.

The sender is the materials management information system (MMIS) or central supply inventory application, and the receiver is the clinical application or EHR that placed the stock order. The ORS message acts as the matching response in a request-response exchange: the care unit orders central stock using an OMS^O05, and central supply returns an ORS^O06 to confirm what will be delivered and when.

When an ORS message is sent

An ORS message is sent once the central supply system has processed the stock requisition. It fires when the warehouse picks the items and confirms the quantity that will be dispatched, flags a requested item as backordered or discontinued, or rejects the entire transaction due to invalid cost centres or delivery locations.

Trigger event

The ORS message type carries a single trigger event:

• ORS^O06 – Stock Requisition Response message.

The trigger O06 pairs with the OMS^O05 stock requisition. The receiving application matches the response to the original request using the placer order number in ORC-2 and the message control ID echoed in MSA-2.

Integration topology

The diagram shows the materials management system returning a stock response through the integration engine to the care unit ordering station.

{{diagram: materials management system → ORS message → integration engine → ordering care unit (EHR / station)}}

Typical senders: materials management information system (MMIS), central supply application, warehouse inventory management system.

Typical receivers: EHR, departmental station ordering terminal, clinical supply management module.

Direction: response in a request-response pattern — central supply responds to the clinical unit's resupply request.

Segments in an ORS message

The ORS_O06 message opens with a header block (MSH, MSA, and optional ERR segments) followed by optional patient/visit context and one or more repeating ORDER groups. Cardinality follows HL7 notation: [X] optional, {X} repeating, [{X}] optional and repeating; a bare code is required. Each segment code links to its canonical field-by-field reference.

[ ] = optional, { } = repeating

Sample ORS message

Note. Constructed for illustration. Item codes, locations, dates, and identifiers are fictional.

MSH|^~&|MMIS|MERCY|NURSESTN|MERCY|20260604090000||ORS^O06^ORS_O06|MSG00048|P|2.5.1
MSA|AA|MSG00047
PID|1||MR98765^^^MERCY^MR||SMITH^PATRICIA^A||19720315|F
ORC|OK|REQ20260604-001^NURSESTN|FIL20260604-001^MMIS||||||20260604090000|||ATT001^JONES^CAROL^^^^MD
RQD|1|IC0042^Sterile Gauze 4x4 10pk^MERCY||HC0042^Gauze4x4^MERCY|5|PK|||3N^301^A|20260604
NTE|1||5 packs picked and dispatched via pneumatic tube.

What this sample shows

The ORS^O06 in MSH-9 marks a stock requisition response. MSA carries acknowledgement code AA (Application Accept) and acknowledges the original request control ID MSG00047. PID associates the response with patient MR98765. ORC carries order status OK (Order Accepted), links to placer order number REQ20260604-001, and supplies the filler order number FIL20260604-001. The RQD echoes the requisition line item code IC0042 and the quantity 5. The NTE adds a comment indicating that the items have been picked and sent.

Working with ORS messages

Matching and Correlation

When an ORS response is received, the ordering system correlates MSA-2 with the outbound request. The placer order number in ORC-2 is used to match individual lines. This correlation is essential for nursing or clinical units to know which of their requests are filled and which are delayed.

Handling Out-of-Stock and Cancellations

If central supply cannot fulfill an item, ORC-5 will carry a status of UA (Unable to Accept) or the message will carry a cancellation code. When an item is backordered, the status may change to SC (Status Changed) or IP (In Progress) with explanatory notes in NTE. Receiving applications should process these status updates to alert the requesting department, enabling them to request alternative items if clinical needs are urgent.

Vendor variance. Inventory systems differ in how they report partial fills. Some systems return an ORS message showing a status of OK (Accepted) but with a reduced quantity in RQD-5 to represent what was actually picked, while others send two separate order groups—one for the filled quantity and another for the backordered quantity. Check your MMIS documentation to handle partial-fill scenarios correctly.

FHIR equivalent

A stock requisition response maps conceptually to status changes on the FHIR SupplyRequest resource, representing updates to the status field (e.g. from draft to active or completed).

The HL7 v2-to-FHIR Implementation Guide publishes no message map for ORS_O06 and no ConceptMap for the RQD segment. Consequently, any FHIR translation must be mapped manually, using MSA-2 and ORC-2 to locate the existing SupplyRequest resource and updating its status or adding procurement identifiers as identifier elements.

Common pitfalls

Pitfall. Neglecting to check ORC-5 order status. Simply matching the placer order number and assuming the request was filled can lead to clinical staff waiting for supplies that were actually flagged as out-of-stock by the warehouse.

Pitfall. Processing responses without checking MSA-1. Parsing an ORS response under the assumption of success when MSA-1 is AE (Application Error) can lead to the ordering system falsely showing a supply order as accepted, while it was rejected by the inventory system.

How Vorro handles ORS messages

Vorro ingests ORS responses over MLLP, validates the application acknowledgement code in MSA, and correlates each response to its originating OMS request. Vorro updates the status of the requisition line items in the ordering EHR based on ORC-5 (Order Status) and passes through the filler order number from ORC-3. Where a FHIR destination is configured, Vorro updates the corresponding SupplyRequest resource state manually, since the HL7 v2-to-FHIR guide provides no published map for this message.

Related messages

• OMS — the stock requisition order message that initiates this response.
• ORN — the non-stock requisition response message.
• ORM — the general order message.

Sources

• HL7 v2-to-FHIR IG — message maps index
• HL7 Messaging Standard Version 2.5.1 product brief