When an individual patient visits his or her doctor with a problem, traditional clinical diagnosis is made and treatment is administered based on the patient’s symptoms, medical and family history and results of lab tests.

In the e-health world of the 21st century, personalized medicine, a new approach to treatment and analysis of patients’ health issues, promises to revolutionize that process. Personalized medicine looks not only at an individual’s symptoms, labs and medical history but at the individual’s unique clinical genetic and genomic markers to determine a treatment program. Because these factors differ for each human being, the disease they carry and how they will respond to treatment will differ as well. Taking this to another level, personalized medicine enables doctors to make accurate predictions and assumptions not only about an existing condition but to make predictions about a person’s potential to develop a disease. This will enable clinicians to treat patients proactively rather than reactively resulting in a better outcome.

Personalized medicine is gathering momentum as evidenced by the significant attendance and enthusiastic involvement of the participants at the recent conference sponsored by Harvard Medical School and The Center for Genetics and Genomics at Partners Healthcare. Although there was general agreement that personalized medicine is now an accepted way to look at the patient, there are also enormous barriers to its widespread use, including:

· Economic factors such as who will receive and who will pay for genetic testing.

· Issues regarding who will be responsible for building the infrastructure needed to support widespread deployment,

· Concerns about how we amass, use, and protect the vast knowledge base that results from genetic tests.

· Legal questions regarding who owns the genetic test data – the patient, the physician, the institution – and whether or not that information can be used for additional research.

· Unresolved issues regarding standards upon which to build a platform for using personalized medicine

· Discussions about how to structure collaborations amongst all the stakeholders (patients, physicians and scientists) so that personalized medicine advances are translated ultimately into better patient care.

E-patients must be part of the conversation that determines where we are going with personalized medicine because personalized medicine uses genomics to focus not only on disease identification tied to a specific combination of genes in an individual, but also on disease prevention and wellness in which everyone has a high stake.

If you were a patient of Dr. Gregory House, you’d be afraid to tell him you’d researched your symptoms on the Internet. House, the lead character on the Fox TV show, would unceremoniously toss his stethoscope at you and proclaim that you are now a doctor as he nonchalantly walked out of his office.

But in the world beyond the television screen, many physicians have come to recognize the value of their patients’ use of the Internet.

And, if you are like most people, you turn to the Internet for health. Eighty-four percent of adult Internet users in the U.S. go online for medical information, according to a 2007 Harris poll. Some of them, like Diana C., believe the Internet saved their life.

The morning after Diana woke up to find a bat in her bedroom, she noticed marks on her shoulder. When they reddened and became itchy, she searched online and identified the marks as bat bites by measuring the distance between the teeth on a life size picture of a bat and comparing that to the marks on her shoulder. She learned that a bat bite can eventually become fatal if not treated within 48 hours.

After rushing to the hospital, Diana saw that the nurse washed her wounds for just 30 seconds, not the five minutes recommended. A doctor told her not to worry about the 48-hour deadline based on his knowledge of rabies in dogs. Diana realized that she knew more about bat bites than some of the professionals treating her. Only through her own vigilant efforts did she receive the care she needed.

Similarly, Jason D. turned to the Internet when his son, who would cough all night, seemed fine at his medical appointments. Jason concluded his son had asthma and requested tests from his son’s doctor that confirmed the diagnosis.

And Saul C. is indebted to the online symptom checker that advised him to seek immediate medical attention when, several days into a cold, his leg began to swell and hurt. He did, despite his fear that the doctor would chastise him for being overweight. The doctor diagnosed and hospitalized Saul with cellulitis and told him that he was lucky he didn’t wait any longer to be treated, and also told him he needed to lose weight.

The Internet is no substitute for a good diagnostician, like Saul’s or Dr. House. Even as a screening tool, the Internet is limited since doctors notice symptoms that you might not, order tests, and expertly consider an abundance of possible diagnoses. However, as Diana saw, doctors may have little experience with particular diseases, and, as Jason learned, a patient’s symptoms may not manifest themselves in the doctor’s office.

The Internet offers immediacy, an advantage at night or on the weekend. It offers anonymity, which is helpful when a symptom seems too embarrassing to discuss with your doctor. It also offers more detailed information than your doctor might have time to provide.

But the Internet also has erroneous information that can lead you to believe that pounds can literally melt away and cures exist for incurable diseases. A recent YouTube video that has been viewed thousands of times depicts a treatment that claims to reverse the effects of the Alzheimer’s disease, for which no cure currently exists. If miracle cures existed, everyone would know about them, including your doctor.

That is one of the reasons you shouldn’t use the Internet in a vacuum. Another is that looking symptoms up online can be confusing — and frightening — when you lack medical expertise, since there are seemingly endless possibilities to consider.

A Pew Internet and American Life study found that 18 percent of online health seekers were confused by the information they found and 10 percent felt frightened by the serious or graphic nature of the information, making it more concerning that only a third of people looking online talked with a doctor or other health professional about the information they found.

“Given that patients are going online, the best thing to do is engage them as partners in care,” said Dr. Bruce Auerbach, president of the Massachusetts Medical Society and a Lexington resident.

He went on to recommend that, when you use the Internet, you “use credible, reliable sites from trusted sources including medical specialty societies, state associations, and recognized organizations such as the American Heart Association and the American Diabetes Association.”

Above all, seek professional treatment immediately if a Web site recommends it or if you aren’t getting better. Talk to your doctor about what you find online, especially if you are confused or concerned. And don’t worry about a scolding à la House.

Finally, if you receive a new diagnosis from your doctor, ask for Web sites where you can learn more about your condition. Chances are, you’ll come away with excellent recommendations.

Lisa Neal Gualtieri is an Adjunct Clinical Professor at Tufts University School of Medicine, where she teaches a course on Online Consumer Health, where e-Patient Dave delivered a guest lecture on Dec. 2. Lisa’s blog on health is at http://lisagualtieri.com.