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According to research published in the BMJ top marks go to followed by Isabel.

Many people google symptoms leading to the ‘Dr Google’ phenomenon where a patient visiting a doctor begins with “I googled my symptoms and..” at which point the doctor inwardly breathes a heavy sigh and prepares to explain that it’s very unlikely that the patient is suffering from a rare case of X, Y or Z!

However, the point of symptom checkers is not to replace medical consultation and diagnosis but to empower patients to be informed so that they can have full discussion with their doctor.

In a response to the study, published in the BMJ, Jason Maude from symptom checker website Isabel says:

“These tools are designed primarily to help the patient become better informed and be able to ask their doctor the right questions. They are not intended to encourage the patient to diagnose themselves and avoid a discussion with a clinician. This is about the patient and doctor working as partners to get to the right diagnosis and receive appropriate care and treatment as soon as possible.”

The Harvard study evaluated 23 of the most popular online symptoms checkers and found that overall “symptom checkers advised the appropriate level of care about half the time, but this varied by clinical severity.” They were also inclined to over estimate risk by encouraging patients to seek care in cases where self care would have been more appropriate. This may be precautionary however as all medical information online has to come with the caveat that patients should consult with a healthcare professional for any medical advice and diagnosis.

Maude further comments that while researching the accuracy of online tools is really worthwhile, it should be noted that when people actually use these services they can use them quite differently. He says:

“The test cases were very medical and very different from the way real patients enter their symptoms. Many, for example, included negatives which patients would very rarely enter. From our experience at Isabel, over 90% of the cases entered by patients include 4-6 symptoms expressed in normal everyday language.

The study did not compare the ease and speed of use. Many symptom checkers require the patient to go through over 20 screens answering questions before they are finally shown the results.

The study also did not look at knowledge provided to users when they were presented with the results to help the patients learn more. This is an important aspect as many of the diagnoses will not mean much to most patients and they need to be shown trustworthy reference resources to encourage them to understand their symptoms better.”

The full results are as follows.

best symptom checkers

 Interesting footnote from Isabel (

Isabel is an award-winning and validated diagnosis decision support system, conceived 7 years ago, as a direct response to the near-fatal misdiagnosis of Isabel Maude, who developed necrotizing fasciitis, a well described complication of chicken pox. Isabel was seen by both the family physician and the local hospital’s ED, all of whom failed to recognize the typical clinical features of necrotizing fasciitis, and sent the patient home.


Full Study: Semigran Hannah LLinder Jeffrey AGidengilCourtneyMehrotra AteevEvaluation of symptom checkers for self diagnosis and triage: audit study


Graphic source: