Since 1997, the HL7 organization has been developing version 3.0 of the protocol. Unlike 2.X versions, HL7 3.0 is based largely on a single formal model called the Reference Information Model, or RIM. The goal of RIM is to reduce the implementation costs of HL7-enabled solutions and further standardize the HL7 communication specifications between healthcare systems.
HL7 3.0 is a complete redefinition of the HL7 standard that is attempting to overcome some of the issues with the current standard. Version 3 will change not only the content of the messages and fields, but also the encoding rules, LLP (low level communication protocols), base data types and even the roles of the applications participating in HL7 communications. XML is the planned medium for HL7 interchange instead of the simple ASCII text that is currently in use.
The difficulties with HL7 3.0 are:
- Despite the length of time it has been under development, the 3.0 standard has not yet been clearly defined.
- Very few health-care facilities have migrated to version 3.0, since this version is not compatible with version 2.X. Applications that support version 3.0 would also need to support version 2.X. Creating an interface between version 2.X and version 3.0 would be difficult and expensive.
Because of these difficulties, version 2.X remains the standard that is used by both healthcare facilities and vendors.