Understanding the Basics of Query-Based Health Data Exchange
Health data exchange is essential to meaningful patient care. Providers must be able to leverage accurate and timely health information at the point of care to achieve improvements to the patient experience, population health, care costs, and provider satisfaction.
Over the past decade, a few technologies have emerged from the pack that enable the sharing of clinical data for specific use cases, namely query-based and directed exchange. But true interoperability still remains out of reach.
In this article, we explore the key technologies enabling present-day health data exchange and highlight the additional capabilities needed for an interoperability strategy to prove truly effective: right data to the right people at the right time.
The evolution of query-based exchange
The last decade has witnessed tremendous digital transformation, most importantly the adoption of electronic health records made possible through the EHR Incentive Programs. The United States can now boast levels of certified EHR adoption among hospitals and physician practices at 96 percent and 80 percent, respectively.
Given that the vast majority of providers use certified EHR technology, capabilities for health data exchange are not only within reach but also at their fingertips. Therefore, providers have the means to engage in health data exchange to begin or advance their interoperability strategy.
Query-based exchange is ideally suited to unplanned care, and a network of networks enables healthcare organizations to query and retrieve valuable information to treat patients based on existing health data. As a foundational element of interoperability, this form of health data exchange is a core capability of existing health information networks.
As defined by Office of the National Coordinator (ONC), query-based exchange allows providers to “search and discover accessible clinical sources on a patient,” which typically occurs in settings where unplanned care is common (e.g., emergency rooms).
As its most basic, query-based exchange involves a provider searching for available information on a patient from other healthcare organizations. Underneath the hood, much more is going on.
To be able to find and retrieve patient information, a healthcare organization must connect to one or many existing health information networks.
In the United States, the eHealth Exchange —formerly, the Nationwide Health Information Network (NHIN) —is the largest network, connecting tens of regional/state health information exchanges, a handful of federal agencies, three-quarters of hospitals, and tens of thousands of medical groups to impact the care of an estimated 120 million patients. At present, 318 organizations are participating in the public-private health information network.
The eHealth Exchange has a counterpart in the industry-driven CommonWell Health Alliance launched by Cerner, McKesson, Allscripts, Athenahealth, Greenway Health, and RelayHealth in 2013. CommonWell enables query-based exchange for 13,421 provider sites across the care continuum and includes outsourced billing, radiology, and labs.
Both networks rely on a common framework to make query-based exchange possible, thanks to a landmark collaborative agreement between CommonWell and Carequality. Simply put, the framework comprises an accepted set of specifications for health data exchange that circumvents the need to reach individual agreements with each institution.
By using the Carequality framework, CommonWell extends query-based exchange beyond its participants to a whole host of other implementers of the Carequality framework and their clients. In fact, the framework is the means for connecting the eHealth Exchange and CommonWell. 
More important to an understanding of query-based exchange are the mechanisms that enable it. The health information networks mentioned above use two profiles from Integrating the Health Enterprise, an initiative with the purpose of improving how health IT systems share data.
The first is Cross-Community Patient Discovery (XCPD) to allow users to locate communities where relevant patient data resides by managing the “translation of patient identifiers across communities” information on the same patient. Upon initiating a patient discovery request, a hub or broker (i.e., eHealth Exchange or CommonWell) queries connected repositories to match a requested patient against patients in the system. The requesting organization receives a response of total available documents found or none at all.
The second is Cross-Community Access, which makes possible the retrieval of patient documents held by other healthcare organizations that agree upon a common set of policies for sharing clinical information. Via the hub, an XCA request for a specific document returns an XCA response containing the requested document(s) (e.g., CCDA, radiology report/image).
As for health data security, no centralized hub or data repository holds any of the information, which would make patient data potentially vulnerable, and the framework holds participating organizations to numerous privacy and security obligations.
Possessing a certain EHR technology isn’t enough. Healthcare organizations must work with their vendors to ensure that this functionality is available to their end users. For example, individual provider sites must activate the CommonWell service and train clinicians to use it within their workflows.
What’s more, the utility of connecting to one or another health information network depends on the availability of patient information. As such, healthcare organizations must consider their options based on their patient population and the number of participating organizations in a given network.
By participating in query-based exchange, providers can provide truly patient-centered care —the right information at the right time —as well as take part in population and public health efforts that rely on the steady bidirectional flow of information.