Highlights of Hl7 version 2.5Copyright Ringholm bv © 2003,2008. All Rights Reserved. Summary
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:
HL7 version 2.5 was released in January 2003. 1. IntroductionWith the release of version 2.5 the number of artefacts has increased yet again.
2. Segment Group NamingOne 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. <INSURANCE> <IN1> .. </IN1> </INSURANCE> <INSURANCE> <IN1> .. </IN1> <IN2> .. </IN2> </INSURANCE> 3. Style guideThe 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:
4. Chapter HighlightsThe 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: ControlThe 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�s 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.
4.1.1 Withdrawn Data ElementsFor 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 ProfilesUp 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 conformance statement states the claim that an application or interface conforms to the specifications contained in a message profile. 4.2 Chapter 3: Patient AdministrationThe following fields used in previous HL7 versions have been deprecated in version 2.5:
4.3 Chapter 4: Order EntryChapter 4 defines a number of new messages related to Imaging and Blood Products:
Chapter 7 defines a new SPM (Specimen) segment. This segment will be mainly used in the following messages:
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.
The following fields used in previous HL7 versions have been deprecated in version 2.5:
4.4 Chapter 5: QueryChapter 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 ManagementUp 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:
4.6 Chapter 7: Observation ReportingChapter 7 defines 6 new result messages related to point-of-care observations and specimen identification:
A new SPM (Specimen) segment has been added to this chapter to improve the identification and specification of specimen. 4.7 Chapter 8: Master FilesChapter 8 defines 3 new messages related to master files:
The new IIM-Segment (Inventory Item Master) contains information related to the availability of inventory. 4.8 Chapter 9: Medical RecordsThis 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: SchedulingThis 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:
4.10 Chapter 11: ReferralsThis chapter of HL7 version 2.5 contains no significant changes. 4.11 Chapter 12: Patient CareThe definition of the ROL segment has been moved to chapter 15 (Personnel Management). 4.12 Chapter 13: Clinical Laboratory AutomationThis chapter of HL7 version 2.5 contains no significant changes. 4.13 Chapter 14: Application ManagementThis chapter of HL7 version 2.5 contains no significant changes. 4.14 Chapter 15: Personnel ManagementIn 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.
One of the fields used in previous HL7 versions has been deprecated in version 2.5:
4.15 Appendix F: Claims and ReimbursementA 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:
These segments are used in a series of new message types:
5. References
[HL7] "HL7", 2003, http://www.hl7.org/, Version 2.5.
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