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10 Conditions Doctors Often Miss

Cancers, heart attack, stroke top misdiagnosis list. Here’s what patients can do 

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Colorectal cancer, lung cancer and breast cancer are the three most frequently missed diagnoses in outpatient clinics and academic medical centers, a January 2022 study published in JAMA Network Open found. Heart attack and prostate cancer round out the top five.

Combing through data from patient safety incident reports, malpractice claims, morbidity and mortality rounds (conferences that review patient deaths and complications), and focus group responses, researchers found 836 relevant diagnostic errors, which they used to identify the 10 most common missed or delayed diagnoses and explore what went wrong in the process. The findings highlight what experts say is a key safety issue in modern medical care.

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“Missed diagnoses are common, and they’re often overlooked,” says study coauthor Gordon Schiff, M.D., associate director of Brigham and Women’s Center for Patient Safety Research and Practice and an associate professor of medicine at Harvard Medical School in Boston.

In fact, research shows that some 12 million American adults are misdiagnosed annually in outpatient settings. That’s about 5 percent of patients, though some experts say the percentage is likely higher. And a new study published in the medical journal BMJ estimates that roughly 795,000 Americans become disabled or die each year because of a misdiagnosis.

10 Most Commonly Missed or Delayed Diagnoses by Medical Condition

Derived from 836 relevant cases from patient safety incident reports, malpractice claims, morbidity and mortality rounds (conferences that review patient deaths and complications), and focus group responses. Reported in JAMA Network Open.

  1. Colorectal cancer
  2. Lung cancer
  3. Breast cancer
  4. Myocardial infarction (heart attack)
  5. Prostate cancer
  6. Stroke
  7. Sepsis
  8. Bladder cancer
  9. Pulmonary embolism
  10. Brain hemorrhage

Previous research supports the findings of this latest report. Nevertheless, a few other conditions can be added: Pneumonia, heart failure, kidney failure and urinary tract infections are among those often missed in the primary care setting, a study published in JAMA Internal Medicine found. Fractures, abscesses and aortic aneurysms are also commonly missed, according to another report published in the same journal.

Why do diagnostic errors occur?

Reasons for diagnostic errors run the gamut. Sometimes it’s miscommunication between patient and doctor: The patient may fail to describe their symptoms accurately, or the doctor misses something important in the patient’s story. Other times an incorrect test is ordered, or a test is read incorrectly. Data in electronic medical records can be disorganized, and sometimes referrals aren’t followed up on.

“It could be so many of those reasons,” even multiple reasons, says Hardeep Singh, M.D., a professor of medicine at Baylor College of Medicine and chief of Health Policy, Quality and Informatics (HPQI) at the Michael E. DeBakey VA Medical Center in Houston.

“You also can’t overlook the fact that “there’s a lot of uncertainty in diagnosis,” Schiff says. There are several thousand known diseases but only so many symptoms.

“When you go to your primary care doctor complaining of a headache, there’s a long list of possibilities [of what might be causing it],” says David Newman-Toker, M.D., a professor of neurology, ophthalmology and otolaryngology and director of the Armstrong Institute Center for Diagnostic Excellence at Johns Hopkins University School of Medicine. The same can be said for stomach pain or back pain.

Another pitfall: when a patient presents with atypical symptoms. If someone is having a stroke and goes to the emergency room with classic stroke symptoms, such as weakness on one side of the body, the diagnosis is rarely missed, Newman-Toker explains. But doctors “miss about 40 percent of strokes that present with dizziness,” which can arise from a myriad of causes, stroke being one of them. (Newman-Toker and his colleagues now use an electronic device that measures eye movements to determine whether a patient’s dizziness is caused by stroke or something more benign.)

Not every missed diagnosis is detrimental to a patient’s long-term health. Back pain can be misdiagnosed as a muscle strain when it’s really osteoarthritis, or one skin condition can be mislabeled as another. “On the other hand, there are a number of diseases that don’t play nice like that,” Newman-Toker says. “Vascular events, infections and cancers tend to be diseases where if you miss them, the consequences for the patient can be devastating and permanent.”


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Research shows these “big three” categories account for about 75 percent of all serious harms from diagnostic errors. 

Patients can help prevent a misdiagnosis  

Can diagnostic errors be prevented? That's a goal that many experts are working toward, and believe it or not, you as a patient can help.

1. Prepare for appointments. Before your appointment, take some time to think through your symptoms and concerns. Write them down and bring these notes with you to the doctor. “This is really about boiling down your symptoms and the timeline of your symptoms into a very simple format [that’s easy for the clinician to digest],” Newman-Toker says. The Society to Improve Diagnosis in Medicine, a physician-led patient safety organization, has a worksheet to help patients outline and organize their medical history, symptoms and concerns.

“If the doctor gets kind of a nice, one-page executive summary or whatever you want to call it, then they’re going to spend more time thinking about the problem and less time gathering the information,” Newman-Toker says.

2. Ask questions. It’s important to ask probing questions about the diagnosis you’re given and why other conditions were ruled out. For example, if bad headaches bring you in and your doctor diagnoses cluster headaches, ask why that’s the case and why it’s not a migraine. 

“What you’re looking for is a reasonable set of answers to those questions,” Newman-Toker says. “You’re looking for a thoughtful explanation, not defensiveness.”

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3. Follow up. Finally, keep track of your progress after a treatment plan is prescribed, and stay in touch with your doctor if things don’t get better. If symptoms persist, it’s common for a patient to assume that the treatment is to blame, not the diagnosis, Newman-Toker says. And if the patient calls the doctor’s office and asks for a medication change or a higher dose, “the doctor won’t rethink the case.” To get a second look, call the doctor and say, “I’m not getting better. Are we sure that I’ve got the right diagnosis?”

“I think people don’t realize how important patients’ voices are in a diagnostic process,” adds Singhwho is also a coauthor on the latest JAMA study. “Because it really helps us not only make the original diagnosis … but also to question the diagnosis later if things don’t get better.”

What is a diagnostic error?  

The National Academies of Sciences, Engineering, and Medicine defines diagnostic error as the failure to establish an accurate and timely explanation of the patient’s health problem, or failure to communicate that explanation to the patient. It can be the result of:

  • A delayed diagnosis
  • A wrong diagnosis
  • A missed diagnosis

Source: Society to Improve Diagnosis in Medicine 

A few other tips: Keep an accurate list of your medications, and bring this with you to all of your appointments. Also, keep your own records of test results, referrals and hospital admissions.

When to get a second opinion

If things don’t get better, or if you are suspicious of a diagnosis and want to confirm it, consider getting a second opinion from another physician, perhaps a specialist. Your doctor may even recommend it.

A study from researchers at Mayo Clinic found that around 20 percent of people who sought a second opinion got a different diagnosis from the first; about 66 percent of patients received a refined or redefined diagnosis when seeking a second opinion.

When asking for a second opinion, be as “direct and unemotional as possible,” the experts at Columbia Surgery in New York City, recommend. Some patients find this part difficult, especially if they have an established relationship with their doctor, Singh acknowledges. “But there are ways that you can express concerns assertively to the clinician, so that they understand what your concerns are,” he says. “And that could be, ‘This is a life-changing diagnosis. I’d like to see a second opinion to make sure we’re on the right track, and I’ll come back to you once I’m able to confirm that.’ ”

When the appointment for your second opinion rolls around, be sure to bring all the details from your previous diagnosis, including test results and recommended treatment plans.

Editor’s Note: This story, first published April 8, 2022, has been updated to include new information.

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