HL7 SSU_U03 (Specimen Status Update) | Integration Soup HL7 Reference Guide

HL7 SSU_U03 Specimen Status Update

Where lab automation reports what happened to a tube or container.

HL7 message structure SSU_U03 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
SSU_U03.SPECIMEN_CONTAINER	Specimen Container group	Yes	Yes
SAC	Specimen Container detail	Yes	No
OBX	Observation/Result	No	Yes
SSU_U03.SPECIMEN	Specimen group	No	Yes
SPM	Specimen	Yes	No
OBX	Observation/Result	No	Yes
ROL	Role	No	No

SSU_U03 reports specimen or specimen-container status from automated equipment to a Laboratory Automation System or middleware layer. Think tube arrived, tube loaded, aliquot prepared, container moved, processing failed, or specimen detail updated as part of an automation line.

The message is about the physical workflow around specimens. It is not the same thing as an ORU_R01 result, though it may include OBX rows for automation-relevant observations.

A small SSU U03 example

MSH|^~\&|TRACK01|CORELAB|LAS|CITYHOSP|20260723101500||SSU^U03^SSU_U03|SSU030001|P|2.5.1 EQU|TRACK01^Automation Track 1^CITYHOSP|20260723101500|BUSY^Busy^HL70365|REMOTE^Remote control^L|N^Normal^HL70367 SAC|||TUBE12345^CITYHOSP||||20260723101430|INPROCESS^In process^L|RACK^Rack^L|RACK7|04 OBX|1|CE|CONTAINERSTATUS^Container status^L||INPROCESS^In process^L||||||F SPM|1|SPEC12345^CITYHOSP||SER^Serum^HL70487|||||||P^Patient specimen^HL70369||||||20260723093000|20260723100000 OBX|2|NM|VOLUME^Available volume^L||2.5|mL^milliliter^UCUM|||||F

What workflow it represents

A device or automation component is telling the receiver where a specimen container is and what state it is in. Receivers use the message to update specimen tracking screens, decide what work can happen next, and detect exceptions before someone walks the line looking for a missing tube.

SSU_U03 is also a place where automation-specific observations can travel without pretending to be clinical results.

How to read the structure

MSH identifies the update, optional SFT identifies software, and required EQU identifies the reporting equipment.

Each SPECIMEN_CONTAINER group starts with required SAC. SAC is the container view: tube, carrier, tray, position, volume, status, and other physical container details. Optional OBX rows under SAC are for extra automation facts about the container.

The nested SPECIMEN group uses required SPM for specimen identity and specimen type. Optional OBX rows under SPM describe specimen-level facts rather than container-level facts.

Implementation traps

The biggest mistake is flattening SAC and SPM into one vague specimen record. The container and the specimen are related, but they are not the same thing. Aliquots, racks, slides, and parent containers make that distinction matter quickly.

Keep container identifiers, specimen identifiers, and accession identifiers separate. When a line jams or a tube is split, those identifiers are how support staff reconstruct what happened.

If OBX is used for automation facts, profile the allowed observation identifiers. Otherwise the receiver gets a stream of local labels that are easy to display and hard to act on.

Reference notes

HL7 v2+ describes SSU_U03 as a message for specimen location and status information. The standard notes that OBX rows attached to SAC can carry automation-relevant information not included directly in SAC.