Googling for Diagnoses


Googling—the use of search-engines such as Google—is a new diagnostic tool in the modern clinician’s armamentarium.

A 2006 study published in The British Medical Journal examined how often searching with Google leads physicians to a correct diagnosis.1 The investigators were blinded to the correct diagnoses and compared the results of diagnostic cases published in the 2005 case records of The New England Journal of Medicine (NEJM) with diagnoses made using Google searches. Their results indicated that Google searches revealed the correct diagnosis in 15 of 26 cases, or 58% of the time. (See Table 1, p. 34.)

The limitations of the study are important to recognize when considering how well a Web-searched diagnosis can compare with one made without Web searching.

In some cases, although Google supplied information that approximated the diagnoses made in NEJM, the researchers thought the diagnoses were not specific enough.

For instance, one case for which Google suggested a diagnosis of extrinsic allergic alveolitis was described in the NEJM case record as extrinsic allergic alveolitis caused by Mycobacterium avium, also known as “hot tub lung.” This exemplifies the point that search engines don’t make diagnoses—people do. Expert knowledge is required to choose the best search words and select among the results.

Experts agree that using search engines for a diagnosis is likely to be more effective for conditions with unique symptoms and most useful in a certain class of diagnostic challenges in which clinical experts are at the helm of diagnostic deliberations.1,2

Table 1. Google Diagnosis vs. Final Diagnosis click for large version

click for large version

The choice of search engines is important and will increasingly affect accurate diagnoses as the technology develops.

“Hospitalists may utilize [Google] less; they are often working in environments [hospitals] that have ready access to more thoroughly vetted sources such as UpToDate, Medline, or MDConsult,” says Joshua Lee, MD, a hospitalist and medical director of Information Services at the University of California at San Diego. “Within Google there are variations on a theme, such as GoogleScholar, which accesses many of the same academic journals as Medline. Given that they are accessing the same journals, many would feel that searching with GoogleScholar is just as accurate as [searching with] Medline—at least as far as the source material is concerned.”

Search engines offer an impressive volume of new scientific material that is indexed daily. But, current search engines cannot identify differences of meaning in symptoms, drug names, anatomic features, or diagnoses.

“The key drawback to using open Google is that you cannot guarantee that the information comes from peer-reviewed journals,” Dr. Lee says. “When a search with ‘regular’ Google brings back untested medical information that is not peer reviewed, it gets dicey, and thus less reliable.”

Current Web technologies may merely be a first step in creating a much more powerful infrastructure for Web-based diagnostics. The so-called semantic Web will allow computers to process meaning in documentation.3 Two key elements of this revolution are the resource description framework (RDF) and Web ontology language (OWL) technologies. These next-generation search tools are being beta tested and will be freely available within the next decade.

There are a number of caveats to using and trusting information from search-engine investigations. Google stands up much better than other search engines in simple diagnostic searches. Also, diagnostic problems are not solved on a linear scale of difficulty.2 Research and development of the benefits of the semantic Web in clinical practice will help maximize this tool for diagnostics. TH

Andrea Sattinger is a frequent contributor to The Hospitalist.


  1. Tang H, Ng JHK. Googling for a diagnosis—use of Google as a diagnostic aid: internet based study. BMJ. 2006 Dec 2;333(7579):1143-1145.
  2. Gardner M. Diagnosis using search engines. BMJ. 2006 Dec 2;333(7579):1131.
  3. Berners-Lee T, Hendler J, Lassila O. The semantic web. Sci Am. 2001 May 1;34-43.

When Patients Google for Diagnoses

Even though Tang, et al.,1 cautioned in their study that patients who use Google to find their own diagnosis may find it less efficient and may be less likely than a physician to retrieve the correct diagnosis, organizations such as the Patients Association in the United Kingdom voiced their concerns that the study might encourage the public to self-diagnose. Their primary concern was the lack of regulation of most sites, leading, at best, to some unreliable information.

This view is shared by Art Papier, MD, associate professor of dermatology and medical informatics at the University of Rochester (N.Y.) School of Medicine and Dentistry. Dr. Papier understands the Internet is a powerful and useful tool for gathering information, but it may also be a risk in the hands of people who do not take the time to identify trusted and high-quality sites.

Research shows that most people limit their searches to the one or two first pages of search engine hits they get. Although sites from the National Institutes of Health or the National Library of Medicine, for instance, might appear at the top of a search list, so can commercial sites whose information is of lesser quality and who may be aggressively marketing a product. “The evidence is that many patients do not take the time to differentiate a good and bad site,” says Dr. Papier. “They just use what they get as the [list’s] top sites. That’s a real problem.”

Dr. Papier is hopeful that as the quality of the search engines improve, many of these commercial sites with limited information will no longer appear at the top of the search.

On the other side of the issue, there are some great Web sites with solid information. The ramifications for hospitalists, says Dr. Papier, largely involve counseling patients to consider the reliability of sites they consult and understand that key search words and the capacity to interpret results is something for which a patient ultimately could use the help of a doctor. Hospitalists who distribute a list of the best sites to consult for a particular diagnosis or treatment to patients upon discharge will be contributing the most to their patients’ well-being.

“With hospitalized patients,” says Dr. Papier, “that is, the patient with cancer or heart disease, for instance, the family may find on the Internet a side effect of a medication and bring it to the attention of the provider, who may have been too rushed to think through that side effect or who was unaware.” This is one way families of hospitalized patients have been using the Internet in partnership with physicians.

“Patients and families are Googling [health info] like crazy,” says Dr. Papier. “It’s somewhat random whether they get quality info. It behooves both hospitals and hospitalists to help patients and family members find the quality sites. More and more it is becoming a part of the responsibilities of patient care in the modern era.” —AS

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