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Health Level Seven (HL7), created in 1987, is an internationally adopted set of standards that dictates the standards, definitions, and formats that health information is transferred or exchanged between systems applications. The HL7 Standard can be separated loosely into two categories; Version 2 (v2) and Version 3(v3).

In real-world operations, the highest percentage of healthcare organizations employ HL7 messaging that uses the 2.3 or 2.3.1 versions of the Standard. V3 is a newer version of the HL7 Standard and only accounts for a small percentage of usage in the real world in interfacing.

In this article, we are going to discuss if HL7v3 is operational in the real world, how it differs from HL7v2, why v3 has not been as successful as v2, and if you can successfully implement HL7v3 into your healthcare business. 

What Are The Difference Between HL7 Version 3 And Version 2?

Despite HL7v3 being a newer version of the HL7 standards, v3 is very similar to HL7v2. The HL7v2 Standard was designed to provide users with an outlined format in which healthcare information could transfer between disparate clinical systems. The v2 Standard was created and designed by clinical interface specialists. Some defining features of HL7v2 include:


  • Supporting batch processing of message file exchanges or transfers.
  • HL7 is defined by encoding rules. Cardinality, default character sets, and groupings.
  • There is an ever-adapting and evolving to local implementation changes or real-world issues that arise.
  • HL7v2 is able to consider the relationship between other protocols (i.e., lower-layer protocols) and the HL7 standard protocol.
  • Support is provided for local variations in data interchanges. This is achieved by allowing additional messages, additional portions of messages, or optional fields.

    Importantly, all 2.X versions are normally backward compatible with the earlier versions. This is because the v2 standards let applications avoid message elements that are not expected.

On the other hand, HL7v3 was influenced not by clinical interface specialists but rather by the government and medical information users. Most notably, v3 is not backward compatible with v2 versions of the HL7 Standard. Thus, creating an issue with the v3 version not being able to communicate with v2 versions without substantial modifications to the user systems and applications.

What Was/Is The Purpose Of HL7v3?

The purpose of Hl7v3 was to increase global adoption of the HL& Standard by addressing the definitive shortfalls and challenges that had been identified in the HL7v2 Standard. The challenges v3 was designed to address include:

  • The lack of well-defined roles for messages and applications that were used in different clinical functions.
  • Not enough of a full solution was provided, with too much flexibility.
  • The data model is implied rather than consistent.
  • The lack of formal methodologies with data modeling creates difficulties and inconsistencies in understanding.


HL7v3 provides users with a full set of messages, terminologies, and data types, with its specification being built around subject domains that provide trigger events, storyboard descriptions, hierarchical message descriptions (HMDs), and domain objects models that are derived from the Reference Information Model (RIM).

Why Has HL7v3 Not Been Successful?

HL7v3 has not been adopted globally as it is firstly a new standard, and it is incompatible with the older widely implemented HL7 v2 versions. If a healthcare business would like to adopt v3, then HL7 V2-based interfaces would need to be created and maintained with v2 applications, all whilst implementing the new v3-based applications and interfaces.

As the implementation of v3 is complex and not user-friendly, v3 has been mainly adopted by users for use in applications that do not have legacy requirements or in regions of their business that have increased government requirements of v3 usage.

When Is HL7 Version 3 Used?

HL7v3 is primarily used when there is a need to implement Clinical Documentation Architecture (CDA) for the exchange of electronic documents. The exchange of electronic documents generally occurs between the patient and provider for quality reporting or public health initiatives.

What Are The Benefits of adapting HL7v3?

While the implementation of v3 will/may require the creation of v2 interfaces and other applications to facilitate communication between the HL7 standards, and this may seem more like more effort than reward, HL7v3 does have some redeeming benefits.

  • A consistent representation of data laterally across the various HL7 domains of interest is provided.
  • Semantic interoperability is the main focus of determining how information is presented in a clinical framework. Semantic interoperability ensures that the receiving and sending systems share the semantics (meaning) of the data being transferred.
  • Users are able to at any time take advantage of the latest and most efficient implementation technologies that are available.
  • There is a universal application, ensuring that standards can have the best possible global impact whilst, being meeting regional and local system requirements.
  • Provides consistent development and provides the user with the ability to manipulate and store the specifications in data repositories, alternatively storing data in word-processing documents.  

What Is CDA?

CDA is part of the HL7v3 and is a document addition standard that defines the semantics and structure of all clinical documents that are transferred between patients and healthcare providers. These clinical documents are defined as having the following characteristics:


  • Persistence
  • Human readability
  • Context
  • Stewardship
  • Potential for authentication and,
  • Wholeness


A CDA would generally contain imaging reports, pathology reports, discharge summaries, physical and admission, etc. The most widespread use for CDA is for inter-enterprise information, for example, US Health Information Exchange (HIE).


HL7v3, although not widely implemented, does operate in the real world despite its complexities and that it is not backward compatible with HL7v2 versions. It provides users with semantic interoperability, consistent development, designed universal application, consistent representation of data laterally across the various HL7 standards, and does indeed cover the shortfalls of the v2 version standards.

Suppose you enjoyed reading this blog article and would like to read more on this topic, head over to our website blog. Suppose you are interested in implementing HL7v3 in your healthcare business or are looking for other services in the health information technology sphere; head over to our services page to see how we can best help you.

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