Getting the right diagnosis

Sharp pain showed up like clockwork whenever Cecilia ate a fat-laden meal. Reeling from stabbing sensations in her upper right belly — and often doubled over from nausea — the 60-something woman would lie in agony for hours. Then, as mysteriously as it appeared, the pain would vanish — and so would Cecilia's concern.

But Cecilia's denial vaporized one night when her abdominal distress became overwhelming and she went to the emergency room. By then, her problem — unaddressed for months — had progressed to a perforated gallbladder, a far more threatening situation than the highly common gallstones that led up to it.

Any significant delay in being diagnosed — regardless of how it happens — is considered one of the many types of diagnostic errors. So is receiving the wrong diagnosis, or a doctor or patient not communicating clearly about it, says Dr. David Bates, a professor in the Division of Medicine at Harvard-affiliated Brigham and Women's Hospital and director of its Center for Patient Safety Research and Practice.

Nearly one in five hospitalized adults are harmed or die each year due to a diagnostic error, according to a study of more than 2,400 patients (average age 64, 46% women), published online Jan. 8, 2024, by JAMA Internal Medicine. But the true incidence is likely to be far higher, since the vast majority of diagnostic mistakes probably aren't recorded, Dr. Bates says. "There's still work to be done around how to best look for these, and to determine how many there really are," he says.

Tricky-to-diagnose conditions

Doctors have relied on autopsy studies for more than 100 years to estimate the proportion of patients who die with diseases that weren't identified while they were living. According to a study published in the January 2025 issue of Archives of Pathology and Laboratory Medicine, pathologists found at least one condition that hadn't been diagnosed prior to death in 98% of nearly 650 deceased patients. The most common were pneumonia (in 31%), coronary artery disease (in 24%), and heart attack (in 15%). It should be noted that some of the conditions likely never produced symptoms that would lead the patients to seek help.

Other research expands our understanding of which conditions are ripe for misdiagnosis. According to a study published in February 2024 in BMJ Quality and Safety, just 15 diseases account for about half of all serious harms from diagnostic errors, and the top five — stroke, sepsis, pneumonia, blood clots in veins, and lung cancer — account for nearly 39%.

What do many of these conditions have in common? "They have relatively subtle symptoms that can be attributed to other causes," Dr. Bates says, "and it can be difficult to sort out when one of those conditions is present."

Who's more at risk?

Not only are certain diagnoses harder to pinpoint, but explicit groups of people are more vulnerable to this scenario. Women and minorities are 20% to 30% more likely than white men to experience missed or delayed diagnoses, the 2024 BMJ Quality and Safety study suggested.

Dr. Bates suspects some people don't speak up if they feel their diagnosis is wrong or if they'd like a second opinion. "If you think something isn't going right, or you're not getting better, you need to advocate for yourself," he says.

Older adults may also be more susceptible to diagnostic errors because of memory issues and heavy medication use. They also tend to have chronic diseases that can complicate the process of diagnosing another condition.

"Older patients tend to have more things wrong with them," Dr. Bates says. "They probably complain less, too, than younger patients — they're more willing to put up with things."

Reasons for error

In general, diagnostic errors are traceable to a handful of causes, as follows.

Clinician error: Perhaps 40% of diagnostic errors fall into this category, Dr. Bates says. Faced with unclear or complex constellations of symptoms that could signal a variety of conditions, "doctors might miss something," he says. "It can be quite tricky to determine a diagnosis from all the things going on."

Delays: Difficulty coordinating a patient's and doctor's schedule, fear of a necessary diagnostic test, or worry about getting a "bad" diagnosis are some common reasons why a delay might occur. For example, he says, only about two-thirds of people with positive stool tests for colon cancer — a type of screening test that detects blood in the stool — promptly schedule a colonoscopy, the gold standard test to detect colorectal cancer. "This is a partnership," he says.

Poor communication: Clinicians may not adequately explain to patients how certain conditions affect them, especially those whose symptoms fly under the radar, Dr. Bates says. But patients can also communicate inadequately. "This can be more of an issue in older patients, who just hope their symptoms will go away," he says. "If you have a really worrisome symptom, it's always best to let your doctor know, and they can make the call whether you should come in or not."

Consequences large and small

Diagnostic mistakes can set off a chain of other problems, meaning

• you may not get the relief you need
• your condition worsens, possibly seriously
• you spend time and money chasing the correct diagnosis
• you become anxious or depressed by the lack of answers.

Fortunately, however, the vast majority of errors are minor and don't lead to dire consequences. "Some are worse and more likely to cause serious problems than others," Dr. Bates says. "But most eventually get sorted out and the patient recovers well."

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