INTERNET - Prognosis is dicey for new Microsoft health record site - Consumers have been slow to use other online medical repositories.

Like other Web-based personal health records, Microsoft's HealthVault is free and will allow consumers to store medical information -- such as vaccination dates and X-rays -- and share what they wish with physicians and relatives of their choosing.

The big question now is whether the tech giant will have any more success at getting consumers to use electronic health records than big health plans have.

"We think they are very important -- perhaps the most important consumer health tool that's been developed over the past decade," said Archelle Georgiou, a physician and executive vice president of OptumHealth, a unit of UnitedHealth Group Inc., one of the nation's largest health insurers.

UnitedHealth has made Web-based personal health records -- chock-full of information culled from medical claims -- available to 24 million enrollees since 2005.

But UnitedHealth, like other purveyors, hasn't seen the kind of uptake it would like. Research shows that only about 7% of consumers are availing themselves of such healthcare management tools.

"You can have the greatest technology ever, and if doctors and patients are not using it, then we're not going to be recognizing the value," Georgiou said.

UnitedHealth recently rolled out a series of radio public service announcements to promote the use of Web-based personal health records, underscoring how vital the information could be in the event of a natural disaster or personal medical emergency.

Aware that privacy is the No. 1 concern for consumers, Microsoft took care to ensure that the information users put in HealthVault would remain under their exclusive control.

"It's the patient's data, and no one else can see it," said Steve Shihadeh, general manager of Microsoft's Health Solutions Group.

"We won't ever sell or mine or use their data."

The information will be stored in a secure, locked down area, separate from Microsoft's other servers, he said.

Solo and small-practice physicians have been slow to convert their patient records to digital files largely because of the cost. But one large group that has -- HealthCare Partners Medical Group -- plans to make Web-based personal health records available to its 500,000 Southern California patients next year.