Keystone Health Information Exchange, whose goal is to provide small hospitals and practices across Pennsylvania with access to digital health records, added four new members to make it one of the largest and most far-reaching data exchanges in the state.

The four health care providers " Presbyterian Senior Living in Dillsburg, Schuylkill Health System in Pottsville, Community Medical Center Healthcare System in Scranton, and SUN Home Health and Hospice in Northumberland " could quadruple the number of users on the system, said James Walker, chief information officer at Geisinger Medical Center.

Geisinger is one of the founders of KeyHIE, along with Bloomsburg Hospital and Shamokin Area Community Hospital.

The exchange serves a potential population of nearly 2.6 million people in central and northeastern Pennsylvania. So far, more than 300,000 patients have signed up to allow providers to access their information.

"We believe adding these providers, along with the data and users they bring, takes us to a critical mass that will draw many other users to the system," Walker said.

Two other providers, Evangelical Community Hospital and the Moses Taylor Health Care System, are due to begin using the exchange this summer.

KeyHIE uses a secure Web browser-based system to allow users to access patient information. That's the kind of low-cost infrastructure that's needed to provide service to small hospitals and physician practices which otherwise don't have the IT expertise to benefit from such digital medical data exchange, Walker said.

"The state government hasn't put a lot of effort or resources into building health information exchanges," he said. "We've tried to build this system so that organizations that have only basic IT can participate."