Last week, when Philipp Lenssen at Google Blogoscoped unveiled screen shots of Google’s health-information system, the warning sirens seemed to drown out any praise for the concept.

Code-named Weaver, the system is designed to be a personal repository of all of an individual’s medical information, which the patient can selectively share with others (such as a physician offering a second opinion). The system is also a resource for information about illnesses, treatments, drugs, health-care providers, and even community sites where patients can share experiences and rate the quality of care they got from particular physicians.

Comments about Weaver warned that Google “could sell [your medical information] to anyone, including insurers and government,” and that insurance providers and employers could hack into your data to deny you coverage or a job.

What gets lost in all this is what Google is trying to accomplish. A careful reading of what Google vice president Adam Bosworth has written and said about his goals paints an impressive picture of what such a service can do.

In a speech at the American Medical Informatics Association Spring Congress, Bosworth outlined three things that we need, which will presumably find their way into a Google Health service.

The first thing we need, Bosworth says, is “discovery.” Finding relevant information is critical to good health. He notes in one blog that his mother died of cancer and that “it took her doctors nine months to correctly identify an illness which had classic symptoms.”

Doctors don’t always pay enough attention and don’t always have the latest information at their fingertips. Patients, armed with the appropriate data, could take more responsibility for their own health.

One year ago, my sister, Lindy, died of breast cancer that had metastasized to her brain. I firmly believe that she died, in part, from a lack of information.

Lindy first felt a lump in her breast in 1998 and was relieved when the mammogram finally came back negative. What she didn’t know, and might have found out if something like Weaver had been around then, is that mammograms can sometimes give false negative results. She ignored the lump for another year. By then the cancer had spread significantly.

She had a radical mastectomy, chemo and radiation therapy, and a bone-marrow transplant to restore her immune system. She went into remission for five years. She kept seeing her oncologist, who did blood tests which all came back negative. Again, we were all fooled. Blood tests are not sufficient for tracking remission, something I later found out through searching Google.

A couple of years ago, Lindy started having trouble concentrating, was sluggish and forgetful, and lost physical coordination. She also suffered from depression, so she talked to her psychiatrist about these symptoms rather than to her oncologist.

It took at least six months for her symptoms to get bad enough for her daughter, fearing that Lindy was having a stroke, to drag her to the emergency room. A CT scan showed several tumors in her brain. These might have been caught sooner if she had been keeping track of all her symptoms, medications, and test results, and had shared them with all her doctors, as future patients will be able to do with Weaver.

Bosworth’s second suggestion is “action.” This means seeking out physicians, treatment centers, support groups, and other organizations to treat the patient or help families care for their loved ones. My family went through the difficult process of finding Lindy home hospice care as her condition worsened. Even then, my brother still needed to spend a great deal of time caring for her, dealing with her insurance, tracking her medications, scheduling visits from nurses, and trying to determine what to do when she further deteriorated. Bosworth says that there should be a simple information and management system to do all those things, as well as to help with e-consulting and care-management guidance, and with requesting second opinions and getting online coaching.

Bosworth’s final suggestion is “community.” From his speech:

Consumers can organize into communities which are protected from inappropriate commercial exploitation but allow consumers to share their experiences with others whose medical situations are similar, to rate the value of resources such as sites and health practitioners, and even to answer questions of each other in real time.

Lindy meant to seek out support groups, and I meant to help her. But we were overwhelmed, physically and mentally. I wish I had managed to overcome those limitations. A system like Weaver would surely have made such groups easier to find and to share information with.

My sister worked for one company for nearly 30 years and had the same health insurance until she died. Her employer and insurer already had all her information, so she had no fear of corporate spies finding out about her condition. Still, Bosworth’s promise is that “only consumers, not insurers, not government, not employers, and not even doctors, but only consumers, should have complete control over how [their medical information] is used.” That promise is worth more to me than all the speculation of what Google “could” do.

Roni Zeiger, a physician and product manager at Google, notes in a blog entry that “better-informed patients recover faster, manage chronic illnesses better and may even avoid some illnesses altogether.”

To that I would add: they may even save their own lives.