Health Care : HL7 Standard

" Health Level Seven (HL7), is an all-volunteer, not-for-profit organization involved in development of international healthcare standards. “HL7” is also used to refer to some of the specific standards created by the organization (i.e. HL7 v2.x, v3.0, HL7 RIM etc.).

HL7 and its members provide a framework (and related standards) for the exchange, integration, sharing and retrieval of electronic health information. "

- Wikipedia

HL7 is a standard for Medical Applications to exchange information.

The Health Care industry segment is divided into many domains such as patient care, laboratory information systems, etc. The HL7 standard enforces a consistency of stored and shared information across many domains in Health Care.

The HL7 standard is continously being developed and enriched with new ideas. The HL7 committee has released six versions of the HL7 standard ( collectively called as HL7 2.x ) :

• 2.1
• 2.2
• 2.3
• 2.3.1
• 2.4
• 2.5

Hl7 2.x is the first widely accepted and commercially successful standard. HL7 v2.x mostly uses a proprietary (non-XML) encoding syntax based on delimiters.

HL7 3.0 is a complete rework of the HL7 standard. HL7 3.0 is an attempt to overcome some of the issues with HL7 2.x. XML is medium for exchange of HL7 messages instead of the simple ASCII text that HL7 2.x used.

The basis of HL7 v3.0 is a model called the Reference Information Model ( RIM ). RIM is an attempt to further standardize the HL7 specifications between health care systems.

The differences between HL7 2.x and HL7 3.x are :-

HL7 2.x

• HL7 2.x is the most popular and the most widely implemented HL7 standard in the US.
  
• HL7 2.x does not have a common information model that spans all Health care domains-of-interest.
• HL7 2.x does not have a robust data type specification.

HL7 3.x

• HL7 3.x is based on the RIM and attempts to bring consistency across the entire standard.
• HL7 3.x defines a common information model based on the RIM.
• HL7 3.x defines a data type specification.
  
• HL7 3.x is NOT backward compatible with HL7 2.x.
  

HL7 V2 is focussed on the exchange of clinical clinical data between applications. However, HL7 V3 is influenced by dedicated people who focus on how health care information is created & how it can be modeled.

HL7 v3.0 is a dramatic shift from HL7 2.x and introduces a lot of new concepts.