Microsoft has launched an online health-care service designed to help patients take control of their health records and monitor their medical conditions.

Microsoft's HealthVault, announced Thursday in Washington, D.C., will allow users to store and share health records online, to collect and manage health data on a variety of home devices, and to search for health information.

"We all know health is incredibly complex, it has lots of information, and we make it harder than it needs to be," said Peter Neupert, corporate vice president of Microsoft's Health Solutions Group. "By making it harder than it needs to be, bad things happen."

Patients want tools to simplify their interactions with the health-care system, Neupert added. "They want an information system ... that puts them at the center, that makes it easy for them to manage their health, and their family, and their activities when they interact with the health system," he said. "It's hard, but it's not that hard. It's possible, and it's possible today."

The HealthVault applications, available for free on the HealthVault Web site, are designed to allow patients to share their information safely and easily with health-care providers and manage their health issues, such as weight loss and long-term diseases, Microsoft said.

The three pieces of HealthVault include:

* HealthVault Search, a specialized search engine designed to give the most relevant online health content and connect results with HealthVault-compatible products.

* The HealthVault repository account, an encrypted online e-health record that users and their families can share with doctors.

* The HealthVault Connection Center, a place where users can find "plug-and-play" drivers for health monitoring devices, such as diabetes meters and heart-rate monitors, to connect to the HealthVault accounts.

"We need to make information reusable," Neupert said. "We're all frustrated ... by the simple, stupid things like having to fill out the clipboard [at a doctor's office] all the time."

The HealthVault was developed in cooperation with privacy advocates, including the bipartisan Coalition for Patient Privacy, Microsoft said. Dr. Deborah Peel, founder of the Patient Privacy Rights Foundation, praised the company for privacy controls on the service, including the prohibition of data transfer without "explicit" informed consent.

"Consumers finally have a trusted place to store their personal health information that will not be data-mined because they alone control it," Peel said.

Microsoft's new e-health platform will probably be the largest not affiliated with an insurance provider or specific employer, said Lynne Dunbrack, program director at Health Industry Insights, a market research and advisory services firm.

But the effort faces several challenges, Dunbrack said. Microsoft is banking on its relationships with outside software developers to create programs that work with HealthVault, she said.

In addition, less than 30 percent of doctors' offices and hospitals now use electronic health records, so it will be a challenge for many users to find data to populate the HealthVault records, she said. Only about 1 percent to 3 percent of U.S. consumers have adopted personal e-health records, she said, despite a major push from U.S. President George Bush's administration and several private groups.

One of the issues is privacy concerns. "Consumers are quite wary of having their personal health information available and accessible over the Internet," Dunbrack said.

Microsoft said more than 40 applications and devices will work with HealthVault now or in the near future. Partners offering applications or devices that will work with HealthVault include: American Diabetes Association, American Heart Association, American Lung Association, Diet.com, Eclipsys, Healthphone Solutions, LifeScan, Medifast, NewYork-Presbyterian Hospital, NoMoreClipboard.com, Texas Instruments, U.S. Wellness, and Vital Data Technology.

Developers interested in building their own HealthVault-based products can download the HealthVault software development kit.

This story was amended on Oct. 5, 2007.