HL7 MDM_T06 Document Addendum Notification and Content

An addendum was created, and the addendum text is included in the message.
HL7 message structure MDM_T02 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
SFT
 Software Segment No Yes
EVN
 Event Type Yes No
PID
 Patient Identification Yes No
PV1
 Patient Visit Yes No
MDM_T02.COMMON_ORDER
 Common Order group No Yes
ORC
 Common Order Yes No
MDM_T02.TIMING
 Timing group No Yes
TQ1
 Timing/Quantity Yes No
TQ2
 Timing/Quantity Relationship No Yes
OBR
 Observation Request Yes No
NTE
 Notes and Comments No Yes
TXA
 Transcription Document Header UAC User Authentication Credential Segment Yes No
MDM_T02.OBXNTE_SUPPGRP
 Obxnte Suppgrp group Yes Yes
OBX
 Observation/Result Yes No
NTE
 Notes and Comments No Yes

MDM_T06 is the document addendum notification with content. It says that a new addendum document has been created for an existing document, and it sends the addendum body along with the document header. The important word is addendum: this is not editing the original report in place, and it is not replacing the original document.

On the wire this is normally MDM^T06^MDM_T02. The T06 trigger describes the addendum workflow; the MDM_T02 structure supplies the content-bearing layout with TXA and one or more OBX segments.

A small MDM_T06 example

MSH|^~\&|DOCSYS|CITYHOSP|EHR|CITYHOSP|20260716103000||MDM^T06^MDM_T02|MDM060001|P|2.5.1 EVN|T06|20260716102800 PID|1||123456^^^CITYHOSP^MR||Smith^Jane^Anne^^Ms^^L||19800314|F PV1|1|O|RAD^XRAY^^CITYHOSP||||55555^Reader^Riley TXA|1|RADADD^Radiology Addendum^L|TX|20260716100000|55555^Reader^Riley|20260716101500|20260716102800|55555^Reader^Riley||||DOC20260716002|DOC20260715001^DOCSYS|ORD448900^EHR|AU OBX|1|TX|ADDENDUM^Addendum text^L||Addendum: Comparison with prior study from 2026-06-10 shows no interval change.||||||F

What systems do with it

The sender is often a transcription system, radiology system, cardiology system, or document repository. The receiver files the addendum, links it to the original document, displays it with the existing report history, and may notify clinicians that new document content is available.

TXA is the document header. For addenda, the receiver cares about the new addendum document ID and the parent/original document relationship. OBX carries the addendum content. If the receiver cannot link the addendum to the original document, it may file a new standalone report and lose the clinical context.

How to read the structure

The generated panel shows MDM_T02 because T06 includes content. The required backbone is MSH, EVN, PID, PV1, TXA, and at least one OBX/NTE support group. Optional common-order groups can link the addendum back to an ORC/OBR order context.

Do not treat the OBX content as the entire final document unless the profile explicitly says to render the original plus addendum that way. Many systems display the original document and addendum as related entries or a composite document.

Implementation traps

The big trap is overwriting the original report. An addendum should preserve the original and add the extra statement. If the receiver replaces the old content with the addendum text, the document history becomes misleading.

Also watch document identifiers. A T06 addendum normally has its own document ID and points back to the parent/original document. If both systems do not agree which TXA fields carry those values, corrections and later replacements get hard to reconcile.

Reference notes

HL7 Chapter 9 describes T06 as a document addendum notification with content, where the addendum has its own document ID linked to the original via the parent ID. Caristix summarizes the same event as an addendum notification with accompanying content. Rhapsody notes that T02, T04, T06, T08, and T10 are the MDM structures that carry document contents in OBX.