 Overview:
The Health Level Seven (HL7) version 3 (v3) standard is a specification
that defines static and dynamic models for messaging among healthcare
applications. The static models define the structure of message
content and the dynamic models define the expected behavior of the
sending and receiving components. The standard itself is partitioned
into domain components, identified as application roles, and the
structure and potential behavior of messages from a sending application
role to a receiving application role are defined by interactions.
An implementation may state what portions of the HL7 Vv3 standard
it supports by specifying which application roles it supports, or
which interactions it is capable of sending or receiving.
Industry
Need Addressed: An interaction defined between sending and receiving
application roles identifies the abstract structure of message content,
which is then mapped to some information technology (e.g. XML) as
the representation on the wire. The dynamic model associated with
the interaction specifies the behavior of the receiving system.
Behavior may include a required response message sent back to the
sender, required information sent to tracker applications and repositories,
state changes to the state of an object identified by the message,
or the raising of additional trigger events that must then be acted
upon by the receiving system. Healthcare stakeholders need an open
experimental testbed where emerging implementations of the HL7 v3
specifications can be tested for interoperability with other emerging
implementations.
NIST/ITL
Approach: NIST is developing an HL7 v3 testbed environment where
healthcare developers can test their application interfaces for
conformance to the HL7 v3 specifications. The test laboratory architecture
includes capabilities to send/receive messages by email, http, mllp,
or other transport protocols identified by HL7, as well as a standard
ebXML registry for registering specific templates, profiles, or
other HL7 v3 artifacts, and persistent storage for all sent or received
messages and all generated message content. Developers of v3-specifications
will be able to define templates of result messages they'd like
to see returned to them, or stored in healthcare repositories, and
reference implementations in the test laboratory will produce response
messages and/or repository content based on those templates. Since
all HL7 v3 specifications are based on object models, with object
oriented messaging, NIST will be able to use its Software Component
Integration Testing methodology to define and populate a Test Harness
that will create and manage a collection of messages to cover the
important behavioral aspects of supported HL7 v3 interactions. In
this manner, an HL7 v3 healthcare implementation can be tested to
see if its supported application roles interoperate properly with
other v3 application roles, thereby determining its conformance
to all HL7 v3-specified application roles claimed in its conformance
profile.
Impact:
Portable and interoperable healthcare information is an important
goal of the entire healthcare industry. Standards-based interchange,
using HL7 specifications and related IHE profiles, is key to reaching
this goal. An open laboratory for testing emerging implementations
of HL7specifications will significantly reduce the cost of achieving
the desired portability of electronic healthcare records and interoperability
among different healthcare providers.
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