HL7 ESR_U02 (Automated Equipment Status Request) | Integration Soup HL7 Reference Guide

HL7 ESR_U02 Automated Equipment Status Request

A direct status poll for analyzer and automation equipment.

HL7 message structure ESR_U02 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
EQU	Equipment Detail	Yes	No
ROL	Role	No	No

ESR_U02 is the request side of the automated equipment status conversation. A Laboratory Automation System, middleware engine, or monitoring service sends it when it wants a specific piece of equipment to report its current status.

The normal application-level answer is ESU_U01. The ordinary ACK only says the request message was received and processed at the messaging layer; the ESU response is the useful status payload.

A small ESR U02 example

MSH|^~\&|LAS|CITYHOSP|ANALYZER01|CORELAB|20260723100600||ESR^U02^ESR_U02|ESR020001|P|2.5.1 EQU|ANALYZER01^Chemistry Analyzer 1^CITYHOSP|20260723100600

What workflow it represents

Use ESR_U02 when the receiver cannot rely only on unsolicited equipment updates, or when an operator needs a fresh status snapshot. It is a narrow request: identify the equipment, ask for status, and expect the equipment to answer with its current state.

This is especially useful after a connection restart, before resuming routing to a device, or when a local dashboard needs to reconcile stale state.

How to read the structure

MSH carries the request event. Optional SFT can identify the requesting software. The required EQU segment names the equipment instance whose status is being requested.

Optional ROL may identify the responsible user or role behind the request, but the important operational contract is the response: the equipment identified in EQU should send ESU_U01.

Implementation traps

Do not use ESR_U02 as a generic command message. It asks for status; it should not be overloaded to start, stop, pause, reset, or reconfigure the instrument.

Also agree whether the request is synchronous or asynchronous. A quick ACK followed by ESU_U01 is much easier to operate than a long-held connection waiting for the device to decide what to say.

If polling is frequent, put guardrails around it. A status request every few seconds from every dashboard can become noise the instrument or middleware did not need.

Reference notes

HL7 v2+ describes ESR_U02 as a request for device or equipment status from one application to another. The equipment identified in EQU should respond using the automated equipment status update message.