RESEARCH Figure 1. Comparison of technical approaches to biosurveillance: A) standardization, filtering, and checking for duplication done at contributor site; B) translation and checking for duplication at pub- lic health site; C) data repository. Methods The electronic reporting system consisted of three par- ticipating groups: data contributors, the clearinghouse, and public health organizations (Figure 2). Four nonaffiliated healthcare organizations of varying size (consisting of 2, 2, 5, and 13 facilities) participated in the system. The small- est facilities were regional care centers with 49 beds each; the largest was an urban hospital with 650 beds. All partic- ipating organizations used the same laboratory information system (LIS) (PathNet, Cerner Corp., Kansas City, MO) to document clinical microbiology results. Microbiology reports were constructed from a combination of codified entries representing the pathogen and discrete observations or free text entries added by the user. The data dictionaries and test catalogs at each organization were unique and were not referenced to standardized vocabularies. During the implementation of the electronic reporting system, the data dictionaries and test catalogs from the participating organizations were uploaded to the data clearinghouse; entries representing reportable pathogens or tests with the potential to yield reportable results were mapped to a stan- dardized vocabulary. We established agreements to assure security within the system. Surveillance data reported to public health organi- zations are exempted from the Health Insurance Portability and Accountability Act. Legal agreements designating the supplier of the clearinghouse system as a business associ- ate with full reporting capability were established with the participating organizations. These agreements, combined with stringent access controls (physical and procedural security measures), encryption of identifiable information, and virtual private network (VPN) secured communica- tions and ensured protection of confidentiality. Interagency agreements between public health organizations in the Kansas City area provided a further framework for the appropriate exchange of data across jurisdictional bound- aries. For example, an agreement between KCHD and the state of Kansas recognized Kansas City, Missouri, as a county of Kansas for purposes of metropolitan surveil- lance. Batch extraction scripts ran daily at each data contribu- tor, pulling new laboratory test orders, laboratory results, and patient demographic information. Demographic infor- mation was encrypted before being transferred to the data clearinghouse through a VPN (Cisco Systems, San Jose, CA). The data were loaded into a data warehouse (Oracle Corp., Redwood Shores, CA) and checked for errors and duplication; data mapping was then performed (Informatica Corp., Redwood City, CA). Microbiologic results identifying reportable pathogens were mapped automatically to a common nomenclature to standardize the varying names between the participating organizations. Procedure orders (i.e., stool culture) deemed relevant to the detection of an infectious disease outbreak were also mapped to a common nomenclature. After these process- ing steps, the results were used to build two reports that were delivered through the Internet to KCHD using a VPN secured account. One report provided trending information on orderable procedures; the other provided results from microbiology tests (Figure 3). KCHD staff reviewed the reports using a report viewer (BusinessObjects Corp., San Jose, CA). Reports summarizing the results reported to KCHD were also delivered to the institution of origin. Figure 2. Data clearinghouse system architecture. Data are extracted from the laboratory information network at contributing sites and encrypted into a flat file. These are then delivered by vir- tual private network (VPN)–secured file transfer protocol to the clearinghouse where they are subjected to data warehousing processes. Jurisdictional filters are applied to the data to construct reports with data appropriate for the recipient. KCHD, Kansas City Health Department; KDHE, Kansas Department of Health and Environment. 1282 Emerging Infectious Diseases • Vol. 9, No. 10, October 2003