PHIN Case Notification Using HL7 v2.5 Messaging - Wisconsin's TB Implementation

The CDC issued new guidance in 2006 that calls for the use of Health Level Seven (HL7) Version 2.5 (v2.5) as the national standard for public health entities to send and receive electronic messages.  Specifications and implementation guides were released which detailed how to format HL7 messages for the transmission of Nationally Notifiable Diseases in general, with separate mapping guides for specific diseases.  In the fall of 2007 the Wisconsin Electronic Disease Surveillance System (WEDSS) project office, along with its vendor, began an effort to generate tuberculosis (TB) case data messages in HL7 v2.5 format.  The software should be in production with daily TB message transmissions to the CDC, by the date of the PHIN conference.

This presentation will describe the WEDSS TB message project from inception to implementation, and lessons learned.  The project was initiated by establishing regular tele-conferences with the CDC to answer questions, and track progress.  Analysis of the specifications and the guides revealed that the TB message is composed almost entirely of data collected on the Report of Verifiable Case of Tuberculosis (RVCT) form.  The steps taken to convert the RVCT form data, stored in an HL7 v3 RIM based database, to the PHIN specific HL7 v2.5 message will be detailed.  Sample topics include the general structure of the HL7 v2.5 message for representing TB data, downloading vocabularies from the PHIN VADS web site, using PHIN specific terms to define observation types, and the use of value sets to codify observation values.  Upon software completion, message validation was performed by the CDC for both format and content.  This was done initially by emailing the messages, and later by direct transmission using PHIN MS.