Supporters describe the rule aspart of a push for interoperability, so that data can be sharedmore easily between the various entities involved in helping aperson be healthy. (Photo: Shutterstock)

Privacy advocates are raising concerns about new rules proposedby the Trump administration that will give private companies accessto the medical records of potentially millions of Americans.

The administration describes its goals as empowering consumers,rather than the companies that will use the data. The proposalwould allow individuals to download their medical records and sharethem with third-party entities, most likely health apps.

Related: Easing regulations on patient data comes withrisks

Supporters describe the rule as part of a push for interoperability, so that data can be sharedmore easily between the various entities involved in helping aperson be healthy, including hospitals, clinics and healthapps.

While it's up to the consumer to share the data in the firstplace, they may have no say over how the information is used afterthey hand it over. Privacy advocates worry that people will providesensitive medical information that they don't realize might bere-sold or re-shared to other entities.

Administration officials insist that the rules will demand techcompanies to be upfront with consumers about how their data will beused. But these assurances are hardly enough for some. Criticsworry this is one step closer to giving the major titans of data ––Facebook, Google and Amazon –– more ways to monitor the lives oftheir customers.

"This is not about interoperability — this is about havingaccess to data," said Jeff Chester, head of the Center for DigitalDemocracy. "The health data is going to give them insights intomany other aspects of your life."

At least one major tech firm, however, is adamantly opposed tothe proposal: Epic Systems, a privately-held company based outsideof Madison, Wisconsin that is the largest provider of software forelectronic health care records.

Epic has begun funding ads in the Washington D.C. Metro opposingthe proposal, warning of dangers to patient privacy. Sixty healthsystems joined it in signing a letter telling the Department ofHealth and Human Services to reconsider the proposal.

However, the fact that more hospitals didn't sign the lettersuggests that some providers perceive an advantage in allowinghealth apps greater access to patient data.

"Their absence represents a thundering silence," David Brailer,who served as National Health Information Technology Coordinatorunder President George W. Bush, tells CNBC. "Many health systemsare quietly discussing how the data access and data fluidityactually benefits them in the long-run."

Read more: 

• Managing medical records via smartphone might takea while to catch on
• Digging deeper: Health data mining platforms surgeahead
• Interoperability may jeopardize consumers' healthcare privacy