Reprinted
from HL7 News
The
official publication of Health Level
Seven, Inc.
August 1999
National
Immunization Program (NIP) contact person:
Susan Abernathy
saa6@cdc.gov
404.639.8177
Report
by: Susan Abernathy; HL7 Board of Directors;
NIP, CDC
A
new implementation guide for data exchange
entitled, "Immunization Data Transactions
Using the Health Level Seven (Version
2.3.1) Standard Protocol," June
1, 1999, is now available and promises
to benefit both developers of immunization
registries and software vendors. This
guide is the culmination of collaboration
by six immunization registry developers
and managers who are ready to test data
exchange with each other The guide defines
the messages in detail, showing how they
are able to carry a rich amount of immunization
data. Equally important, however, the
new guide also defines the "minimum
message" needed for a billing system
to extract the core data elements and
send them to an Internet account or save
to a file, creating an unsolicited batch
of updates to the immunization histories
in a registry. The minimum message consists
of the core demographic and vaccine event
data elements plus values in all the
additional HL7-required fields.
The
registries involved in producing this
guide (California, San Bernardino (in
CA, but with a separate, privately funded
registry), Georgia, Illinois, Michigan
and New York State) had developed their
own individual implementation plans,
but now intend to implement this common
standard. In addition, staff from both
Kaiser Permanente and the Indian Health
Service participated in conference calls
and draft reviews as the work proceeded.
These organizations provided new viewpoints
to the effort, which was initiated by
the National Immunization Program (NIP)
of the Centers for Disease Control and
Prevention (CDC). As other immunization
registries evolve to be ready for data
exchange outside their boundaries, NIP
intends to coordinate any additional
data
needs
through HL7 so that over time there will
remain one nationally consistent implementation
of Immunization messaging for those who
choose to participate.
Catalyst
for the Guide
The
guide is a result of a meeting in the
fall of 1998, when representatives of
the six immunization registries shared
information about how each one planned
to implement the HL7 Version 2.3 immunization
messages. Each of the six registries
had produced an implementation guide
describing how they would implement the
HL7 messages. NIP staff charted each
field as described by each registry to
allow easy and visible comparisons of
the differences. Many minor and some
major differences were evident. For example,
one registry planned to carry the birth
name in one field and the current name,
if different, in another field. The other
registries had these reversed. Several
registries also had designed Z-segments
to carry information they had not seen
a standard way to send. Others had developed
their own code tables for user-defined
codes Even though some of the table elements
were similar the codes varied among registries
that defined their own. It was apparent
that communication among these registries
would not be seamless and that an opportunity
existed to create an implementation guide
that could meet everyone's needs and
at the same time form the basis for a
national standard.
The
registries agreed that all would benefit
if they adhered to one national standard
implementation guide that could be available
both for registries to use and for software
vendors to build into, the provider systems
they produce. One vendor explained that,
with one national implementation, software
vendors would be more ready to incorporate
it into the clinical or computer-based
patient record systems they were building
or upgrading. Another vendor advised
that, even though his product was strictly
a billing system, he believed it would
be possible to build a "patch"
that could extract the needed data and
save it to a file as services were performed
in the clinic. At the end of the day,
a batch of records could be forwarded
to the registries, thus eliminating the
need for duplicate data entry. A nationally
standard implementation that allows vendors
to assure their customers of compatibility
with all registries and that meets the
needs of all registries will save time
in the development cycle that might have
been allocated to attempting to solve
data exchange issues in isolation.
The
Recent Standards Work
From
fall 1998 through spring 1999, NIP staff
addressed each of the issues raised by
representatives of the six registries
and developed a method for reporting
them within the Version 2.3.1 standard.
When new codes were needed for tables
already in the standard, NIP staff requested
the additions from the relevant chapter
work groups within HL7. Version 2.3.1
contains some of these additions, and
others will be in Version 2.3.2. As additional
registries decide to leverage the work
of this group, further changes likely
will be needed from HL7. Besides the
new fields and codes added to the HL7
standard itself, NIP staff requested
and received new LOINC codes. These codes
allow more specialized reporting of clinical
data related to the vaccine event, such
as the dose number of each component
of a combination vaccine or a contraindication
to the vaccine that is due.
The
Need for Registries
NIP
participates in this effort as part of
its support for the development and maintenance
of computerized immunization registries
as an essential resource to provide the
information needed to improve and sustain
high levels of immunization cover- age.
Several factors frequently work together
to cause missed opportunities to vaccinate:
- The
recommended immunization schedule is
increasingly complex, as new and combination
vaccines are developed.
- Providers
frequently overestimate the proportion
of patients that are fully immunized.
- Most
parents do not know the immunization
status of their children.
- Most
providers do not send parent reminders
when a child's immunization is due
or recall them when an immunization
is missed.
- Physicians
frequently do not have access to a
child's complete immunization history
because of scattered records, created
by the increasingly mobile society
and the changing nature of healthcare.
Immunization
registries can reduce these missed opportunities
by making available the information needed
to address each of them;
- electronically
determining what immunizations are
needed at each encounter,
- providing
calculations of actual coverage levels,
- producing
immunization status reports for parents
during child care visits,
- automating
the sending of reminder notices to
parents,
- bringing
together fragmented records to produce
one complete immunization history.
The
Challenge
Immunization
registries face similar technical challenges
to those faced by most of the healthcare
industry today--how to enable communication
between numerous disparate systems. Registries
have been developed by a number of different
entities-managed care organizations,
states, cities, counties, and local communities.
These developers chose the methods they
wished to use within their own systems,
but without a coordination point this
approach resulted in different hardware,
platforms, and applications that need
to communicate with each other when a
patient moves from one area to another
area.
HL7
as Part of the Solution
NIP
recognized the potential importance of
HL7 to enable immunization registries
to exchange data with each other in 1995.
With the help of HL7 members, NIP developed
four messages to allow both public and
private immunization providers to exchange
immunization data with their local or
state registry. The messages were designed
to communicate the elements in NIP's
core data set. The core data set consists
of 16 demographic elements used to identify
the patient and eight elements that define
the vaccine event. The core data set
had been developed by consensus of a
working group of Immunization grantees
and reviewed by the National Vaccine
Advisory Committee. The messages are
(1) a query for an immunization. record
(VXQ), (2) a response when multiple matches
to the query are found (VXX), (3) a response
when the query is matched and a record
returned (VXR), and (4) an unsolicited
update to an immunization history (VXU).
These messages are defined in HL7's Version
2.3 at Sections 4.10 through 4.14 of
the standard.
The
Beginning
Most
state-based immunization registries were
introduced to HL7 in August 1995 at a
workshop of registry developers and managers.
Dr. Clement McDonald provided the keynote
address, giving an overview of standards
and showing the importance of HL7 to
clinical reporting. An overview of the
messages themselves was presented, and
a first implementation guide describing
how registries could use the standard
messages was distributed by NIP. At the
time, most registries were still in the
initial stages of planning and working
through the issues involved with collecting
the needed data and reporting from local
registries to a state registry. Most
registries planned to address private
provider participation at a later date,
so the benefit of the HL7 messages did
not seem immediate. From that initiation,
immunization registries have evolved
to the point where 61 of the 64 state
or local registries who are immunization
grantees are in some stage of registry
development or implementation, several
have significant private provider participation,
and several are ready to test and implement
an HL7-based data exchange.
The
Future
Continued
collaboration among registries and providers
to ensure that implementation plans meet
messaging requirements will enable registry
developers, vaccination providers, and
vendors of physician systems to achieve
communication compatibility not available
previously. Just as importantly, a national
standard that meets the needs of all
developers can save time and money in
the development cycle that might have
been allocated to solve data exchange
issues in isolation. The core data set,
current vaccine table, current vaccine
manufacturers table, and implementation
guide are available on the NIP website
at www.cdc.gov/nip/registry.
For additional information or to provide
feedback on this article or the referenced
documents, please contact Susan Abernathy
or Julie Waddell at (404) 639-8245.
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