The government is incentivizing doctors to begin using the electronic health record (EHR), but only about half of U.S. doctors have worked the EHR into their daily workflow.

All doctors will probably use the EHR eventually, but another problem awaits.

People see an average of 18 different doctors within their lifetimes. So even if all the health data generated in those visits was captured electronically, it wouldn’t magically land in a single patient record.

The unified patient record — or “one patient, one chart” — for the most part, doesn’t exist.

“It can be done, but it’s challenging; I think we are quite far away from it today,” said Ryan Howard, CEO of the cloud-based EHR company Practice Fusion.

(Note: Ryan Howard will be speaking about electronic health records at VentureBeat’s HealthBeat conference in San Francisco Oct. 27 and 28.)

Howard has plenty of experience with health data integration. Before he started Practice Fusion he was hired to unite Brown & Toland Medical Group’s thousands of patient records — to make all patients’ data available to all doctors across the clinics in the group.

“You have 660,000 doctors in the U.S.; about half of them are using an EHR,” Howard says. “The other half are still using paper — and there is really no difference between the two.”

By this Howard means that because the data, whether on a proprietary EHR or on paper, is still trapped inside provider walls, and can’t sync up with other patient records elsewhere.

Howard says the main problem is that most patient records systems are not built on cloud platforms. They aren’t built to share data, but rather to keep behind clinic or hospital walls.

“If the doctor is using a system like Epic they can’t send clinical data out of that EMR to another doctor [using another system],” Howard said. “With our system, any user can share data with doctors on and off the platform.”

Howard explains that data can be sent from the Practice Fusion cloud to doctors on other systems via fax or electronically. Or, Practice Fusion can give the recipient a free license to its platform and share it directly via the same cloud.

There may also be unspoken competitive reasons why providers don’t actively try to share clinical data. “A lot of times the hospital isn’t incentivized to share the data,” Howard says. He says hospitals probably aren’t guilty of preventing data from being shared across systems, but probably aren’t going out of their way to enable it either.

“They’re not building walls, but they’re not building bridges either,” Howard says.

But the technical challenge shouldn’t be underplayed. EHR systems from different vendors are built, organized, and formatted very differently. And there’s no overarching standard that dictates how the EHR must be set up in order to sync well with other systems.

There are clinical data sharing standards like HL7 and C-CDA, but many providers have not upgraded their EHR systems to support the standards.