The development of the HL7 is proceeding along two lines. Much effort is being spent on solving the ambiguities of version 2.1 and in extending the standard to areas that are not yet well defined. For example, at a recent working group meeting new messages were defined for dealing with pharmacy records, specifically those relating to IVs. As the number of vendors implementing the standard and as the number of organizations using the standard increase, the standard will continue to be refined and expanded along current formats. As often as possible, these efforts will be "backwards compatible" and may be implemented by vendor choice as the need arises. These changes will be distributed as chapter updates to the current release. A parallel effort is underway that will add formality to the development of the standard. These efforts incorporate a number of case tools, including data modeling. The biggest advantage of this approach will be to reduce significantly the ambiguity in data element definitions. Completeness and correctness of data relations will be enhanced as well. New approaches to documentation, including an object-oriented specification of the data model, will increase understandability. There are still a number of domain-specific areas in which the standard needs to be defined and examples generated to show how the standard applies. Forms of data transfer other than text must be accommodated. HL7 again will take advantage of existing work in these areas, such as the work of American College of Radiology/National Equipment Manufacturers Association (ACR/NEMA) in standards relating to image transfer. HL7 will continue to move toward OSI-compatibility.(ABSTRACT TRUNCATED AT 250 WORDS)