Google Inc. plans to store medical records to test a service whereby people can retrieve their health information whenever they want them.

Between 1,500 and 10,000 patients at the Cleveland Clinic volunteered in the pilot project, which would give them the possibility to have information about their prescription, allergies, and medical histories placed in the system, the Associated Press reported.

The new Google system will not be available to the public and will be protected by a password.

However, the health venture may draw the fire of privacy watchdog groups who already believe Google knows too much about the interests and habits of its users as its computer log their requests and store their e-mail discussions.

Google has not specified a timetable for unveiling the health service, but Marissa Mayer, the Google executive overseeing the health project, has previously said the service would debut in 2008, the AP wrote.

“We believe patients should be able to easily access and manage their own health information,” Mayer said in a statement supplied by the Cleveland Clinic.

A Google representative did not want to comment on the company’s plans, which the AP learned from the Cleveland Clinic, a not-for-profit medical center founded 87 years ago. The clinic already keeps the personal health records of more than 120,000 patients on its own online service called MyChart.

Google’s health system is not the first dealing with patients’ medical records. Microsoft Corp. introduced a similar service last October called HealthVault and it has commitments from medical centers including New York-Presbyterian Hospital and the Mayo Clinic. AOL co-founder Steve Case is backing Revolution Health, which also offers online tools for managing personal health histories.

The new health program was welcomed by other medical centers, which had already expressed their intention to sign up for the health service.

“This is truly a patient-controlled health record, and that’s a very significant step in the drive toward a more consumer-oriented system of health care,” said Dr. John D. Halamka, chief information officer of the Harvard Medical School.

Google sees its expansion into health records management as a logical extension because its search engine already processes millions of requests from people trying to find information about injuries, ailments, and appropriate treatments.