Symptom Checker Websites Miss Millions of Emergencies, Study Warns

A new study found that online symptom checkers are wrong more often then they’re right. (Photo: Getty Images) 

We all do it: You get sick and immediately go online to research your symptoms. Depending on the findings, you might set up an appointment with your doctor to get an expert diagnosis, or not since the website has told you that you malady is probably no big deal. 

New research out of Harvard Medical School has found that symptom checkers could be a dangerous habit, because it turns out that they’re wrong a whopping 66 percent of the time.

In the study, researchers used information from 45 standardized patient vignettes (clinical cases that are often used to measure a medical student’s ability to properly diagnose a condition) on 23 different free online symptom checkers based in the U.S., U.K., Netherlands, and Poland.

The vignettes were divided into three categories: Emergency care required (for example, with a pulmonary embolism), non-emergency care required (a middle ear infection), and self-care (a viral upper respiratory infection).

Here’s what they found: Symptom checkers provided the right diagnosis first only in 34 percent of the evaluations, listed the correct diagnosis within the top 20 possible diagnoses given in 58 percent of cases, and provided the right advice for next steps 57 percent of the time.

The sites gave the correct degree of urgency surrounding the condition in 80 percent of emergency cases, 55 percent of non-emergency cases, and 33 percent of self-care cases.

The overall accuracy of advice varied by website, ranging from 33 percent to 78 percent. The most accurate U.S. websites included Healthy Children (73 percent accurate), Steps2Care (71 percent), and Symptify (70 percent).

Related: What Doctors Wish They Learned in Medical School 

While more than 70 percent accuracy seems pretty decent without having to visit a doctor, that still leaves a pretty big chance that you’ll get inaccurate advice.

But lead study author Ateev Mehrotra, MD, an associate professor of health care policy and medicine at Harvard Medical School tells Yahoo Health that it’s still not a bad idea to use these sites: “Symptom checkers definitely have useful benefits. For instance, they are a better alternative than simply using a search engine to look for health advice.”

Shahan Chowdury, MD, a board-certified physician with Diamond Physicians in Frisco, Texas, agrees. “Given that today’s medical market of greater insured people outnumber the availability of competent medical providers, patients need a place of reliable information to make an initial assessment of their condition,” she tells Yahoo Health, adding that symptom checker sites can help people prioritize their plan of action.

She also points out that the amount of time people spend with their doctors is getting shorter and shorter, and the more valuable and important information you know to give (which a symptom checker site can help you determine), the better your outcome.

But receiving a diagnosis from a computer — or anyone that hasn’t properly examined you — leaves the possibility open that certain important health factors and symptoms will be missed. “There’s no way that a non-human interface like a computer would be able to detect some things that would be picked up during an exam,” Jack Jacoub, MD, a hematologist and medical oncologist at MemorialCare Cancer Institute at Orange Coast Memorial Medical Center in Fountain Valley, Calif., tells Yahoo Health.

Related: The 6 Absolute Worst Things You Can Do for Your Health 

If you’re planning to check your symptoms online (and, let’s be honest, you probably are), Jacoub says it’s important to keep a few things in mind.

First, make sure you’re comfortable with the website that you’re using. Look for some sort of quality measure or certification, as well as a sign that it adjusts its data as new research becomes available.

Next, consider your own preexisting health conditions and family history. “If you or your family members have a litany of health problems, the seemingly-small symptoms you have might be a big deal,” Jacoub points out.

Finally, consider the timeframe of your symptoms. If you’ve just had them for a few days, Jacoub says it probably doesn’t hurt to rely on a symptom checker site — at first. But if your symptoms don’t improve or you have a long-standing issue, it’s time to see your doctor.

And, of course, all Internet diagnoses should be taken with a grain of salt. Notes Jacoub: “They can be counterproductive sometimes because people will think they have leukemia when it’s really a simple iron deficiency.”

Bottom line: Search with caution, and see your doctor if your symptoms persist.

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