Nov. 10 (Bloomberg) -- Google Inc.'s search engine guided doctors to the correct diagnosis of symptoms more than half the time, suggesting the Internet tool may help crack complicated cases, Australian researchers wrote in a medical journal.

Physicians carry an estimated 2 million facts in their heads to fulfill their role in determining what ails patients and how to treat it, doctors including Hangwi Tang of the Brisbane, Australia-based Princess Alexandra Hospital wrote in a study on British Medical Journal's Web site. Google gives users access to more than 3 billion articles on the Internet, they said.

``Web-based search engines such as Google are becoming the latest tools in clinical medicine, and doctors in training need to become proficient in their use,'' the researchers said. ``Our study suggests it's often useful to `Google' for a diagnosis.''

Tang got the idea for the study after evaluating a 16-year- old water polo player who showed up with a blood clot. Tang began to tell the patient's father that the cause of the condition was uncertain, when the father said it was Paget-von Schroetter syndrome. The father had put the symptoms, which include pain and circulation problems in the arms and shoulders, into the search engine and arrived at the correct diagnosis, the doctors wrote.

The doctors did a Google search for 26 difficult-to-diagnose cases published in the New England Journal of Medicine last year, using three to five search terms. They included conditions such as the human form of mad-cow disease. The searches found the correct diagnosis in 58 percent of the cases, the researchers said. That percentage excludes some cases where Google found the correct diagnosis and wasn't specific enough.

`Unique Symptoms'

``We suspect that using Google to search for a diagnosis is likely to be more effective with unique symptoms and signs that can be easily used as search terms,'' the researchers wrote. ``Searches are less likely to be successful in complex diseases with non-specific symptoms or common diseases with rare presentations.''

Google was used for 45 percent of U.S. Web searches in September, according to ComScore Networks Inc., a market researcher in Reston, Virginia. Unlike clinical decision support programs, Google, the world's most popular Internet search engine, is easier to use and is available free of charge, said Tang and colleague Jennifer Hwee Kwoon Ng.

Patients doing a Google search may find it less efficient and may be less likely to reach the correct diagnosis than physicians, they wrote.

To contact the reporter on this story: Martijn van der Starre in Amsterdam vanderstarre@bloomberg.net

Last Updated: November 9, 2006 19:01 EST