CAMBRIDGE, Mass. (CBS Connecticut) — A new study from the Harvard Medical School finds that people who self-diagnose online are accurate nearly half the time.

WBUR reports that of the 23 websites Harvard researchers looked at, half the sites had the right diagnosis among their top three results. Fifty-eight percent of the websites had the correct diagnosis in their top 20 suggestions, while a third listed the correct diagnosis as the first suggestion.

“Users of these tools should be aware that their performance is not perfect by any means, there’s often inaccuracies or errors,” Dr. Ateev Mehrotra, the study’s lead author, told WBUR.

Mehrotra stated that these websites should not be replacing doctors.

“[They are] better than just a random Internet search, but they are not a replacement for going to the doctor and getting a full evaluation and diagnosis,” Mehrotra told WBUR. “They are simply providing some information about what might be going on with you.”

Researchers combed through 45 patient cases of those that used to teach medical students how to reach a diagnosis. They then put the patient symptoms into the online tools and checked the results.

“We’re always trying to improve, but if most of the time the diagnosis is included in the list of possibilities, that’s all we’re attempting to do,” Dr. John Wilkinson, editor of the Mayo Clinic’s symptom checker, told WBUR, adding that “it’s designed to be a starting point.”

The study also found that patients used symptom checkers more than 100 million times last year.

“It’s been very surprising to me that while most doctors know patients are going to the Internet to search for medical advice, in terms of these symptom checkers, I’ve been surprised that few of my colleagues even knew they existed,” Mehrotra explained to WBUR.