1.5 HISTORY OF HL7 DEVELOPMENT
The HL7 Working Group has met approximately every three to four months since March 1987 to develop and review this specification. The group is structured into committees to address each of the functional interfaces under development, with additional committees to address the overall control structure and various administrative aspects of the group. These committees have the responsibility to author and maintain the chapters in the HL7 Interface Standard. In addition, from time to time various special interest groups are formed within HL7 to develop ideas and sponsor particular perspectives that are not covered by any single existing committee. If a special interest groups activities warrant and a new chapter is considered necessary, they may petition the HL7 Technical Committee Chair and the Executive Committee to form a Technical Committee.
In the initial three meetings, a version 1.0 draft Standard was prepared covering the overall structure of the interfaces, ADT, order entry, and display-oriented queries. Although the patient accounting system was recognized as very important, the time frame did not allow it to be addressed in the first draft. This draft was presented to a Plenary meeting of the overall group in Tysons Corner, VA, on October 8, 1987.
Version 2.0 was prepared subsequent to Plenary I in Tysons Corner and presented at Plenary II in Tucson in September 1988. Since Plenary II, editing and revisions for version 2.1, 2.2, and then 2.3 have been ongoing and the Working Group has grown to nearly 300 individuals, far exceeding its original size of 12 and the following has been accomplished:
a) specifications for the various functional areas have been refined and expanded.
b) formal liaison was developed with several other standards efforts: the ANSI HISPP (Healthcare Information Standards Planning Panel) for the coordination of healthcare standards efforts that has since been replaced by the ANSI HISB (Healthcare Information Standards Board), the ASC X12N group for external EDI Standards, the ASTM E31.11 group for Clinical Data Exchange Standards, the ACR/NEMA DICOM group for standards relating to imaging and other aspects of Radiology Information Systems, and the IEEE P1157 group for medical data interchange (MEDIX).
c) the generic control structure was modified, on the basis of comments, to be adaptable to a wider variety of communications environments and to facilitate cooperation with other standards groups.
d) a chapter on the interface to a patient accounting system has been added.
e) a chapter on the reporting of ancillary results, clinical trials, product experience and waveform data has been prepared, harmonized with the ASTM 1238-91 Standard and with the direct, active participation of members of the ASTM E31.11 committee.
f) a chapter with a set of transactions to support the synchronization of master files between related information systems has been added.
g) a chapter on the interface to applications that support medical record functions including transcription management, chart location and tracking, deficiency analysis, consents and release of information.
h) a chapter on messages to support the communication of various events related to the scheduling of appointments for services or for the use of resources has been added
i) a chapter defining the message set used in patient referral communications between mutually exclusive healthcare entities has been added.
j) a computerized data dictionary of all data elements and other message components has been created. Appendix A contains cross references and other information generated from this electronic data dictionary.
k) inconsistencies and mistakes which were discovered in the previous versions 2.0, 2.1, and 2.2 of the Standard have been addressed and documented in version 2.3.
l) extensive additions have occurred in the Order/Entry and Clinical Observations Chapters to include data element oriented results, pharmacy orders and administrations interface.
m) message acknowledgments have been extended to include a separate enhanced mode that defines the "accept acknowledgment." While this mode of acknowledgment has always been allowed, it is now obvious how HL7 supports any environment when intermediaries exist in the network with implicit time delays (such as store and forward services, "Interface Engines" that perform fan out services, etc.). Immediate acknowledgments are available to release the sending system from the need to resend the message.
n) distinctions have been documented between the HL7 abstract message definition which is purely a level 7 (application level) definition vs. the HL7 encoding rules for converting an abstract message into a string of characters that comprises an actual message. These encoding rules are actually a suggested potential alternative where a fully defined level 6 (presentation level) definition does not exist (e.g., ISOs ASN.1 Basic Encoding Rules (BER)).