Technical architecture of ONC-approved plans for statewide health information exchange.

ONC-approved state plans for HIE were reviewed for descriptions and depictions of statewide HIE technical architecture. Review was complicated by non-standard organizational elements and technical terminology across state plans. Findings were mapped to industry standard, referenced, and defined HIE architecture descriptions and characteristics. Results are preliminary due to the initial subset of ONC-approved plans available, the rapid pace of new ONC-plan approvals, and continuing advancements in standards and technology of HIE, etc. Review of 28 state plans shows virtually all include a direct messaging component, but for participating entities at state-specific levels of granularity (RHIO, enterprise, organization/provider). About ½ of reviewed plans describe a federated architecture, and ¼ of plans utilize a single-vendor "hybrid-federated" architecture. About 1/3 of states plan to leverage new federal and open exchange technologies (DIRECT, CONNECT, etc.). Only one plan describes a centralized architecture for statewide HIE, but others combine central and federated architectural approaches.