Millions of patients each year are misdiagnosed and treated for the wrong disease. A report in The Journal of the American Medical Association estimated that between 40,000 and 80,000 hospital deaths a year in the US are due to misdiagnosis. In autopsy studies, researchers have found that doctors misdiagnosed illnesses between 20% and 40% of the time.

What Goes Wrong?

According to the International Disease-Classification System, there are more than 13,600 possible diagnoses. It’s impossible for any human being to consider—or even remember—that many possibilities.

Medical students are taught to play the odds—to think of the most obvious diagnosis rather than something more rare. This approach is useful for narrowing the list of possibilities, but it invariably means that some conditions will be overlooked.

Example: For a sore throat, your doctor probably will tell you to wait it out. Or if the pain is extremely severe, he/she might recommend a rapid throat culture to test for strep throat.

However, there is another bacterial infection that is at least as common as strep throat but not as well-known called F-throat (the organism is F. necrophorum). It doesn’t show up on rapid-culture tests. It doesn’t respond to the same antibiotics, and it can be much more dangerous.

Why do doctors miss it? Because they aren’t looking for it.

How to Protect Yourself

Here’s what you can do to help your doctor diagnose you properly…

  • Encourage your doctor to repeat what you’ve said. Studies have shown that doctors tend to listen to patients for only 18 seconds or less before ­interrupting. Much of what patients say after that is overlooked or ignored.

A doctor who doesn’t listen may miss important information about symptoms, the history of the problem, etc. To make sure this doesn’t happen, ask your doctor to repeat back all of the key information. This allows you to verify that nothing important has been confused or left out. A nice way to say this is, “Doctor, can you please summarize what I have told you? I want to make sure that I didn’t forget anything important.”

  • Ask, “How sure are you about the diagnosis?” You always should ask this question. Doctors routinely take a mental shortcut known as anchoring. They quickly latch onto an idea about what’s causing your symptoms. Once this occurs, they stop thinking about other possibilities.

Example: In the book How Doctors Think, Dr. Jerome Groopman recounts a case in which a woman went to the emergency room because of a fever and difficulty breathing. The ER doctor had recently treated dozens of patients with pneumonia and assumed that she had the same thing. The doctor anchored this conclusion even though tests didn’t indicate pneumonia. It turned out that the woman’s symptoms were due to an aspirin overdose, a possibility that the doctor hadn’t considered.

Asking the doctor to confirm his confidence in the diagnosis provides an opportunity for him to at least consider other possibilities.

  • Ask, “Could something else be causing my symptoms?” This is another important question that pushes the doctor to keep an open mind. Make sure that your doctor takes at least some time to consider other conditions that could be causing your symptoms.
  • Prioritize your discussion. In many HMOs and other busy practices, doctors try to limit patient visits to as little as seven minutes. That’s not enough time to hear a patient’s whole story and discuss diagnostic possibilities, tests, medications, etc.

Before you arrive at the doctor’s office, jot down a list of your most important issues. It might include new symptoms, where in your body you’ve experienced discomfort, when the problem started, etc.

In a short office visit, you’ll be lucky to get the doctor’s undivided attention for the top three issues, let alone more than that, so it’s important to discuss the most important issue first. Example: If you’re having chest discomfort, don’t start the discussion by talking about knee pain.

If you have a lot to discuss, you may also want to let your doctor know this at the start of the visit.

  • Follow up on tests. One study found that doctors mistakenly failed to report abnormal test results to patients one out of 14 times. In some practices, about 25% of abnormal reports aren’t passed on to patients.

Failing to tell patients about unusual results can be dangerous or even deadly. Terry, my wife and colleague, had a glucose-tolerance test because her doctor suspected that her fatigue was due to a form of hypoglycemia. The doctor never called back, so we assumed that the test was normal. It was not. She only discovered this months later when another physician looked at her chart and saw the test result.

Important: If your doctor orders tests, ask the doctor—or the nurse or lab technician—when the results will be ready. Call then and ask about the results and for a written report.

  • Always get a second opinion if you’ve been diagnosed with something serious or if your doctor is uncertain about the diagnosis. A second opinion often differs significantly from the first diagnosis—so sometimes a third opinion is needed before you can make a wise decision about treatment.

Example: We knew a young woman who had a suspicious-looking mole. The biopsy report said that it was the very serious skin cancer melanoma, and she was scheduled for surgery immediately. Her parents insisted that she get a second opinion. A leading expert looked at the biopsy and concluded that it was not melanoma but a benign growth and that surgery was not necessary. A third opinion confirmed the second opinion.

Getting additional opinions saved her from unnecessary worry and an unnecessary surgery.