Key Differences Between HL7 V2 and V3
December 12th, 2007 by David Li
Posted in CDA, HL7 Standards, HL7 Standard
In the HL7 Standard, there are two versions that people think of - Version 2 (V2) and Version 3 (V3). Outlined below are some of the differences between V2 and V3.
HL7 V2
- Not “Plug and Play” - it provides 80 percent of the interface and a framework to negotiate the remaining 20 percent on an interface-by-interface basis
- Historically built in an ad hoc way because no other standard existed at the time
- Generally provides compatibility between 2.X versions
- Messaging-based standard built upon pipe and hat encoding
- In the U.S., V2 is what most people think of when people say “HL7″
HL7 V3
- Approaching “Plug and Play” - less of a “framework for negotiation”
- Many decades of effort over ten year period reflecting “best and brightest” thinking
- NOT backward compatible with V2
- Model-based standard built upon Reference Information Model (RIM) provides consistency across entire standard
- In the U.S., when Clinical Document Architecture (CDA) is what most people in the U.S. think of when people say “HL7 V3″
Learn more about preparing for HL7 V3 or more about the HL7 standards, including HL7 V3, through an in-depth white paper entitled The Evolution of HL7 (PDF).
For a 15-minute recorded presentation on HL7 V3, please click here.
Last 5 posts by David Li
- Key Differences Between HL7 V2 and V3 - December 12th, 2007
- Preparing for HL7 V3 - October 10th, 2007
- ORM vs. RDE for HL7 Pharmacy Orders - July 2nd, 2007
- What Is an RDE Message? - July 2nd, 2007


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