Health information exchange and directory services: Public health's role

(1) Background: Directory services are an important component of health information exchange (HIE) and a key component of many HIE architectures. Many types of directory services are useful, including lookup of individuals, organizations, and service offerings. The national discussion is focused primarily on entity-level provider directories and individual-level provider directories that might be made available to facilitate interoperability. Requirements for Meaningful Use especially encourage the deployment of provider directories to facilitate those transactions. (2) Objective/purpose: To describe how the notion of directory services has evolved, and how public health can play a part in their creation and use. (3) Methods: Many State-level HIE projects consider directory services to be one of the elements of common infrastructure that are required to promote HIE within (and even between) states, even if statewide infrastructure goes little beyond that. There are no ready-made directories, however, of potential state health information exchange participants, though there are a number of potential candidate sources of directory information. (4) Results: There are a number of technologies already in use which may offer some opportunities to standardize directory services, though they do not all provide equivalent functionality and no clear winner has yet emerged. "Push" transactions may have stronger requirements for both entity-level and individual-level directories, as one needs to not only be certain as to the destination of a transaction, but also the security of that transaction needs to be assured. Specific case studies from several state HIE programs will be examined. (5) Discussion/conclusions: Public health agencies have a lot to gain from participation in directory services, both as potential suppliers of authoritative directory data and as users of directory data in interoperability transactions. This activity can continue to keep public health at the forefront of HIE activities.