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1 HL7 v2+ - HL7 v2 refactored - Working Draft! (99.0)

This is the working draft for what is preliminary called HL7v2+. It is subject to change without any notice. Furthermore, it should be kept confidential. No distribution allowed.

2 Welcome to HL7 v2+® (99.0)

HL7 v2+ is a standard for health care data exchange, built as a successor of HL7 v2.x, and published by HL7®.

First time here?
See the full Table of Contents.

Introduction to this standard (chapter 1).

Table of Contents

Level 1 Basic framework on which the specification is built.

Level 2 Vocabulary

Level 3 Building Blocks

Level 4 Domains

Level 5 Conformance

Level 6 Implementable Technology Specification

Level 7 Core Profiles

Data Type Flavors

TBD01390: This is where profile components like official data type flavors should be listed.

Implementation Guide Registry

TBD01450: This is where implementations begin and guides should be listed. Maintaining the implementation guides on this platform will be too tedious, so that a list with hyperlinks should be sufficient.

3 Complimentary Explanation on how this documentation is structured (99.0)


Basics for HL7 v2.x


Encoding manages the transformation from the logical models to serialized data.

  • AMS: Abstract Message Specification
  • ER7: Encoding Rules 7 = vertical bar syntax
  • v2.xml: Encoding using XML
  • JSON: we need to think about that


There are different means of transport:

  • Files
  • MLLP
  • HTTP

TBD (00025)


Text Profiles

Chapter 2B should go there!

TBD (00035)


The content (events message structures, etc.) will be organized into domains to get rid of the chapter view.

The tricky thing is when generating the contents peresumably in a single step, which ssections should be left out and replaced by appropriate links? How to mark then? Also, for the skipped content we need a link back to where it is used. Here, if we see the message structures, we need a list of links telling us where this specific message structure is used.

TBD (00045)

Message Structure

Currently there is a list of the message structures with links to the details. Do we need context information within those pages? Or do we need to group them together, eg. By message type?

TBD (00053)!


This is a list of segments

TBD (00061)


Vocabulary will take care of the updated vocabulary model allowing for harmonizing with other product lines. We need to clarify

  • Links/Names in segments and data types: what is that?
  • How to represent: Vocabulary domains, value sets and code systems? We have enhanced/updated/corrected the representation and management of tables. We should not violate the work done!

TBD (00069)

Data Types

List of all Data Types

TBD (00077)

Please be aware, that this is an intermediate version. We need to add an explanation here telling readers what has been changed and why.

The following changes were applied to improve the way the standard is written: