How to Prevent Medical Diagnostic Errors

Every physician has probably incorrectly diagnosed a patient at some point over the course of his or her career.

In general, the rate of medical misdiagnosis is estimated to be about 10% to 15% (Arch Intern Med. 2005;165:1493-1499). A 2014 study found that two-thirds of 681 respondents to an online survey conducted by the American Association of Otolaryngology-Head and Neck Surgery (AAO-HNS) reported an event in the last six months that they felt should not have happened (Otol Head Neck Surg. 2014;150:779-784). Diagnostic errors were reported in five cases, two of which resulted in major morbidity, and errors in testing were reported in 24 cases, seven of which resulted in major morbidity.

“In surgical specialties, misdiagnosis carries a risk of major morbidity,” said Rahul Shah, MD, co-author of the AAO-HNS study and an otolaryngologist at Children’s National Medical Center in Washington, DC. “When we get it wrong, it leads to big problems.”

The Study of Errors

Diagnosis is never going to be perfect, said Mark Graber, MD, senior fellow in healthcare quality and outcomes at the research institute RTI International. “There are 10,000 different diseases, and atypical presentations are not unusual. The available evidence suggests that physicians get it right about 90% of the time.”

Maybe that’s good. But, Dr. Graber’s question is, “Can we do better?”

Answering that question has become Dr. Graber’s primary mission. In 2011, he founded the Society to Improve Diagnosis in Medicine, and in 2014 he launched the journal Diagnosis.

Dr. Graber believes that one of the best ways to improve diagnosis is to study how errors occur in the first place. In a 2005 study, he and his colleagues studied 100 cases of diagnostic error in internal medicine, collected from five large academic medical centers (Arch Intern Med. 2005;165:1493-1499). In a small number of cases (7%), the mistake was deemed no fault: The disease presented in a very unusual way, or patient behavior undermined the diagnosis. Another 19% of misdiagnoses were system-related errors, such as equipment failure or communication breakdown. In 28% of the cases, cognitive errors on the physician’s part were to blame—either faulty knowledge, faulty information gathering, or faulty synthesis of the data. In 46% of cases, both systems and cognitive errors played a role.

Physicians who did not know enough or who did not get enough information were evident in Dr. Graber’s analysis, but the type of cognitive error that happened the most was in synthesizing information into a diagnosis. In 321 instances of cognitive error, faulty synthesis played a role 83% of the time. For example, physicians overestimated the importance of a symptom, were distracted by patient history, failed to apply appropriate heuristics, or prematurely settled on a diagnosis.