Certainly, it is terrible to be diagnosed with a serious illness. Even worse? Having a serious illness that doctors misdiagnose, leading to delays in treatment, and potential worsening of your health. Conversely, a misdiagnosis can lead to you receiving unneeded treatments, possibly introducing medication and treatment side effects. Fortunately, there are steps you can take to reduce your risk of diagnostic error.

What exactly is a misdiagnosis and how common is it?

A diagnostic error is any mistake or failure in the diagnostic process that leads to a wrong diagnosis, a missed diagnosis, or a delayed diagnosis.

Critically, research shows diagnostic error rates of diagnostic error rates of 10-15%, causing about 10% of patient deaths. Experts believe it is “likely that most people will experience at least one diagnostic error in their lifetime, sometimes with devastating consequence”.

Interestingly, a study published in 2014 found that about 5% of US adults (approximately 12 million people) are misdiagnosed in outpatient settings every year. Concerningly, the study’s authors estimate that about 50% of these errors could potentially be harmful.

Alarmingly, a 2022 study by the Agency for Healthcare Research and Quality estimates that out of the 130 million annual visits to US emergency departments, roughly 7.4 million (about 6%) people are inaccurately diagnosed every year. Furthermore, these diagnostic errors led to as many as 250,000 deaths, while another 370,000 patients suffered serious harm. These diagnostic errors included failures to identify serious medical conditions like stroke, sepsis, and pneumonia.

What are the top missed diagnoses?

A 2022 report outlines a comprehensive review of diagnostic errors by a team of doctors. The group analyzed malpractice claims, patient safety incident reports, and morbidity and mortality reports to create this list of the top 10 missed diagnoses, in order of frequency (from highest to lowest):

Diagnosing an illness can be tricky because doctors must use their judgment and experience, along with test results, to determine possible causes of ailments. Moreover, every patient is different, and symptoms can vary. Additionally, as time passes and more information becomes available (through testing, etc.) the diagnosis can change.

Experts say a good diagnosis requires “communication, openness, humility, and teamwork — with the patient as a key member of the team.” However, this process can be hampered by timid patients, doctors interrupting patients, and rushed appointments.

What causes diagnostic errors?

One analysis gathered focus groups of doctors to analyze 836 diagnosis cases. Importantly, their goal was to identify where the diagnosis went wrong, and what factors made the diagnosis harder than usual.

Interestingly, the most common failures in the diagnostic process were, in order of frequency from highest to lowest, were:

Failure to order a needed test.
Failure to consider the correct diagnosis.
Lack of follow-up, or a delay, for an abnormal test result.
Failure to properly consider a critical piece of the patient’s history.
Delay, or failure, to order a referral.

In addition to these 5 most common diagnostic issues, the study also identified other diagnostic pitfalls, as follows:

Mistaking one disease for another.
Misinterpreting test results – taking the test’s limitations into consideration.
Failure to recognize atypical presentations, signs, or symptoms.
Failure to recognize the urgency of a diagnosis.
The dangers of intermittent symptoms, which may be absent at the time of an appointment or test.
Failure to consider a drug or environmental cause.
Confusion regarding a patient’s observable response to a treatment.
Failure to appreciate the limitations of a physical exam.
Presuming that a chronic disease is the cause of new symptoms.

Another study provides insight into diagnostic errors.

Interestingly, one study provides insight into all the ways the diagnostic process can breakdown. Researchers analyzed diagnoses provided during primary care visits at a large VA facility and found that 80% of diagnostic errors were due to process breakdowns in 5 areas:

Patient-doctor appointment issues, related to:

Patient history
Physical exam
Ordering diagnostic tests

Diagnostic test issues:

Tests not performed
Incorrectly performed tests
Tests interpreted incorrectly

Follow-up issues:

Doctors not following-up to learn of abnormal diagnostic test results
Lack of scheduling follow-up visits with the patient, after abnormal results

Referrals issues:

Lack of appropriate actions from follow-up appointments with other physicians
Communication breakdown between doctors

Patient issues:

Delay in seeking care
Non-adherence to treatments and medications
Not following doctor’s advice
Not attending doctor’s appointments

Confident doesn’t equal correct.

Importantly, don’t let a doctor’s confidence give you a false sense of security about your diagnosis.

Simply put, doctors, like all humans, tend to make assumptions and stick to them. For example, diagnostic error expert Mark Graber, MD, said “clinicians often make the wrong diagnosis when they’re absolutely certain they’re right — and this happens often too quickly, upon seeing the patient and barely getting started with an exam.”

Certainly, doctors are likely to base a diagnosis on seemingly similar cases they have treated before. However, research shows that being confident is not a reliable indicator of whether a diagnosis is correct. Importantly – just because your doctor seems confident doesn’t mean he/she is right!

Additionally, another team of researchers found that confident doctors make diagnostic errors. In this study, doctors diagnosed 4 cases – 2 easy and 2 more complicated. Although the doctors only correctly diagnosed 5.8% of the difficult cases presented, their confidence in their diagnoses was high.

Importantly, this can cause patient harm since doctors who feel confident in their diagnosis may not consider other options. For instance, confident doctors may be less likely to deliberate further, order additional testing, refer patients to specialists, and use reference materials for research. And they may discourage patients from getting a 2nd opinion.

Additionally, doctors often mistakenly believe they won’t make a diagnostic error. Lastly, many believe diagnostic errors usually involve rare diseases, which is not always the case.