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Highlights of Hl7 version 2.5

Copyright Ringholm bv © 2003,2008. All Rights Reserved.
See http://www.ringholm.com/docs/00710_en.htm for the latest version of this document.
Author: Frank Oemig - Associated Sr.Consultant, Ringholm bv
Document status: Draft, version 0.2 (2003-06-04)
Please send questions and comments to frank@oemig.de.


A number of new events, segments, messages and an entire chapter have been added in HL7 version 2.5. It can be clearly seen that some of the experiences gained during the development process of the HL7 version 3 standard are being ploughed back into the development of version 2. HL7 version 2.5 is more consistent and supports more functionality than any of the previous 2.x versions. The changes in comparison to version 2.4 are however relatively small.

The highlights of version 2.5 in comparison to 2.4 include:

  • Improved documentation of the data types (Chapter 2B);
  • The definition of a message profile methodology allowing for an exact specification of messages (Chapter 2);
  • Better support for imaging (IHE) by means of a new segment and a new order message (Chapter 4);
  • Support for orders related to blood products (Chapter 4);
  • A new message that supports diagnoses/procedure messages in 'update' mode (Chapter 6);
  • A new specification of claims and reimbursement messages (Appendix F, informational).

HL7 version 2.5 was released in January 2003.

1. Introduction

With the release of version 2.5 the number of artefacts has increased yet again.

version 2.5 artefacts statistics
The apparent reduction in the number of data types is related to the CE-data type. This data type has been replaced by the more specialised data types CNE and CWE. In combination with reference tables this adds another 160 data types to the amount shown, resulting in an amount that is higher than in version 2.4.

2. Segment Group Naming

One particular change has been finalized in all chapters: the definition of segment group names. The process of naming the segment groups was initiated with the release of version 2.3.1 and is of prime importance for the XML-encoding of HL7 version 2 messages.

The fact that a segment occurs repeatedly within a message can be easily detected. However if the segment occurs repeatedly as part of a repeating group (e.g. the segment group { IN1 [IN2 IN3] } which has segment group name 'INSURANCE') the process of parsing the message can be simplified by identifying the name of the segment group within the message. See below for an XML-instance example.


3. Style guide

The style guide defines how the HL7 version 2 standard is to be documented. Next to a series of small changes a couple of issues have been addressed which will make it easier to work with the HL7 documentation:

  • The definition of the data types using tables;
  • The addition of segment group names to the specification;
  • The component-documentation contained within a description of a field is automatically generated. This to avoid having to change all data type / component references if the definition of a data type is changed.

4. Chapter Highlights

The various paragraphs below describe the highlights of the changes made to the individual chapters of the HL7 version 2.5 standard, when compared to version 2.4.

4.1 Chapter 2: Control

The most important change in Chapter 2 is related to a much-improved way of specifying the data types. The structure of data types is now detailed in tables structured akin to those that detail the definition of segments. This increases the accessibility of the data type definitions and allows for an exact definition of properties such as maximum component lengths and reference tables. Exact data type definitions are a prerequisite for the encoding of HL7 messages using the XML syntax.

The support for the CM data type has been discontinued. A large number of alternative data types has been introduced to replace the CM data type.

A number of new fields have been added to the ERR segment, these allow for a precise identification of the error. These new fields replace the functionality as previously offered by the ERR-1 field "Error Code and Location".

Two new segments have been added to this chapter. OVR allows a sender to override specific receiving application´┐Żs business rules to allow for processing of a message that would normally be rejected or ignored, SFT contains additional information about a software product used as a sending application.

  • OVR - Override Segment
  • SFT - Software Segment

4.1.1 Withdrawn Data Elements

For the first time ever a data element has been declared as being 'withdrawn and removed' from the standard. Field MSA-5 'delayed Acknowledgement Type' was deprecated in version 2.2. Because of its age and the presence of later versions, HL7 version 2.2 doesn't qualify as an official ANSI standard anymore, which is the reason to remove the entire data item from the segment definition. In order not to cause a renumbering of fields in the segment, the definition of the field will be changed into an 'anonymous' field without any data type definition.

4.1.2 Message Profiles

Up to this HL7 version it wasn't possible to unambiguously determine whether or not an application is conforming to the HL7 standard. Paragraph 2.11 of version 2.5 describes the new Message Profiling methodology, which allows for an exact definition of a message structure.

Definition: An HL7 message profile is an unambiguous specification of one or more standard HL7 messages that have been analyzed for a particular use case. It prescribes a set of precise constraints upon one or more standard HL7 messages.

A message profile contains the following information:

  • A definition of the transmitted data;
  • A specification of the message format used to transmit the data;
  • A specification of the responsibilities of both the sender as well as the receiver.

A conformance statement states the claim that an application or interface conforms to the specifications contained in a message profile.

4.2 Chapter 3: Patient Administration

The following fields used in previous HL7 versions have been deprecated in version 2.5:

  • MRG-2 "Prior Alternate Patient ID" (CX)
  • PD1-4 "Patient Primary Care Provider Name & ID No.2 (XCN)
  • PID-4 "Alternate Patient ID - PID" (CX)
  • PID-9 "Patient Alias" (XPN)
  • PV1-52 "Other Healthcare Provider" (XCN)
  • PV1-9 "Consulting Doctor" (XCN)

4.3 Chapter 4: Order Entry

Chapter 4 defines a number of new messages related to Imaging and Blood Products:

  • O23 - OMI - Imaging order
  • O24 - ORI - Imaging order response message to any OMI
  • O25 - RDE - Pharmacy/treatment refill authorization request
  • O26 - RRE - Pharmacy/Treatment Refill Authorization Acknowledgement
  • O27 - OMB - Blood product order
  • O28 - ORB - Blood product order acknowledgment
  • O29 - BPS - Blood product dispense status
  • O30 - BRP - Blood product dispense status acknowledgment
  • O31 - BTS - Blood product transfusion/disposition
  • O32 - BRT - Blood product transfusion/disposition acknowledgment
  • O33 - OML - Laboratory order for multiple orders related to a single sample with multiple containers
  • O34 - ORL - Laboratory order response message to a single specimen/multiple order OML
  • O35 - OML - Laboratory order for multiple orders related to a single sample with multiple containers
  • O36 - ORL - Laboratory order response message to a single specimen/multiple order OML

Chapter 7 defines a new SPM (Specimen) segment. This segment will be mainly used in the following messages:

  • O21 - OML - laboratory order message und
  • O22 - ORL - general laboratory order response message to any OML.

A number of new segments have been defined. The IPC (Imaging Procedure Control) segment is used in orders related to imaging and is a result of the ongoing integration efforts (a.k.a. IHE) between HL7 and DICOM. The TQ1 and TQ2 (Timing/Quantity) segments are a replacement of the TQ-data type. TQ1 and TQ2 allow for a detailed specification of time interval/quantity relationships, these are especially relevant when it comes to the administering of pharmaceutical products.

  • BPO - Blood product order
  • BPX - Blood product dispense status
  • BTX - Blood Product Transfusion/Disposition
  • IPC - Imaging Procedure Control Segment
  • TQ1 - Timing/Quantity
  • TQ2 - Timing/Quantity Relationship

The following fields used in previous HL7 versions have been deprecated in version 2.5:

  • RXE-1 "Quantity/Timing" (TQ)
  • RXG-3 "Quantity/Timing" (TQ)
  • OBR-27 "Quantity/Timing" (TQ)
  • ORC-7 "Quantity/Timing" (TQ)

4.4 Chapter 5: Query

Chapter 5 contains little new functionality. Its contents have been reorganized and rewritten to clarify the various query/response mechanisms and the way they are to be used.

4.5 Chapter 6: Financial Management

Up to now the messages in chapter 6 only allowed for the exchange of a complete set of diagnoses/procedures. A new BAR^P12 message has been created that allows for updates related to a (sub-)set of diagnoses and procedures. The segments relevant to diagnoses (DG1) and procedures (PR1) both have been extended by 2 fields. These fields contain a reference ID of the (sub-)set of diagnoses/procedures and an action-code (i.e. Insert/Update/Delete).

The following fields used in previous HL7 versions have been deprecated in version 2.5:

  • PR1-11 "Surgeon" (XCN)
  • PR1-12 "Procedure Practitioner" (XCN)
  • PR1-8 "Anaesthesiologist" (XCN)

4.6 Chapter 7: Observation Reporting

Chapter 7 defines 6 new result messages related to point-of-care observations and specimen identification:

  • R22: OUL - Unsolicited Specimen Oriented Observation Message
  • R23: OUL - Unsolicited Specimen Container Oriented Observation Message
  • R24: OUL - Unsolicited Order Oriented Observation Message
  • R30: ORU - Unsolicited Point-Of-Care Observation Message Without Existing Order - Place An Order
  • R31: ORU - Unsolicited New Point-Of-Care Observation Message - Search For An Order
  • R32: ORU - Unsolicited Pre-Ordered Point-Of-Care Observation

A new SPM (Specimen) segment has been added to this chapter to improve the identification and specification of specimen.

4.7 Chapter 8: Master Files

Chapter 8 defines 3 new messages related to master files:

  • M13 - MFN/MFK - Master File Notification - General
  • M14 - MFN/MFK - Master File Notification - Site Defined
  • M15 - MFN/MFK - Inventory Item Master File Message

The new IIM-Segment (Inventory Item Master) contains information related to the availability of inventory.

4.8 Chapter 9: Medical Records

This chapter of HL7 version 2.5 contains no significant changes. A new CON (Consent) segment has been added to this chapter for future use, it isn't actually used in any message in this version of the standard.

4.9 Chapter 10: Scheduling

This chapter of HL7 version 2.5 contains no significant changes.

One of the fields used in previous HL7 versions has been deprecated in version 2.5:

  • SCH-11 "Appointment Timing Quantity" (TQ)

4.10 Chapter 11: Referrals

This chapter of HL7 version 2.5 contains no significant changes.

4.11 Chapter 12: Patient Care

The definition of the ROL segment has been moved to chapter 15 (Personnel Management).

4.12 Chapter 13: Clinical Laboratory Automation

This chapter of HL7 version 2.5 contains no significant changes.

4.13 Chapter 14: Application Management

This chapter of HL7 version 2.5 contains no significant changes.

4.14 Chapter 15: Personnel Management

In order to be able to transmit data related to (authentication related) Certificates a new CER (Certificate detail) segment and 2 new messages (listed below) have been added to this chapter.

  • B07 - PMU/ACK - Grant Certificate/Permission
  • B08 - PMU/ACK - Revoke Certificate/Permission

One of the fields used in previous HL7 versions has been deprecated in version 2.5:

  • PRA-6 "Practitioner ID Numbers" (PLN)

4.15 Appendix F: Claims and Reimbursement

A new chapter related to claims and reimbursements has been added to version 2.5. It has not been finalized yet so it was added as an appendix instead of a chapter. The contents of the appendix are based on the Canadian NeCST-standard as well as on German and Swiss legal requirements related to claims messages. Note that the U.S. uses the X.12 message standard for claims and reimbursement.

In order to be able to transport the data related to claims the segments listed below have been created:

  • ADJ - Adjustment
  • HDR - Secondary Header Segment
  • IPR - Invoice Processing Results
  • IVC - Invoice Segment
  • PMT - Payment Information
  • PSG - Product/Service Group
  • PSL - Product/Service Line Item
  • PYE - Payee Information
  • RQI - Request for Information
  • SEC - Security Segment

These segments are used in a series of new message types:

  • E01 - Submit Health Services Invoice
  • E02 - Cancel Health Services Invoice
  • E03 - Query Health Services Invoice Status
  • E04 - Re-Assess HealthCare Services Invoice
  • E10 - Edit/Adjudication Results
  • E12 - Request Additional Information
  • E13 - Additional Information Response
  • E15 - Payment/Remittance Advice
  • E20 - Submit Authorization Request
  • E21 - Cancel Authorization Request
  • E22 - Query Authorization Request
  • E24 - Authorization Response
  • E45 - Query Eligibility

5. References

[HL7] "HL7", 2003, http://www.hl7.org/, Version 2.5.

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Ringholm bv is a group of European experts in the field of messaging standards and systems integration in healthcare IT. We provide the industry's most advanced training courses and consulting on healthcare information exchange standards.