The Ubiquitous Problem of Misdiagnosis in Medicine

What defines a misdiagnosis, or a “diagnostic error” in medicine?

In 2015, the National Academies of Sciences, Engineering, and Medicine’s “Improving Diagnosis in Health Care” defined a diagnostic error as “the failure to establish an accurate and timely explanation of the patient’s health problem(s) or (b) communicate that explanation to the patient.” This comprehensive report provides a granular description of the many contributors to misdiagnosis, noting the respective roles of the clinician, the team, and the system in this many-faceted issue. The concept of an accurate and timely diagnosis delivered in an understandable way to the patient reflects the overall patient-centeredness of the document, which casts the patient and as appropriate, the patient’s family, as not only an advocate but also as a key informant in his care.

An analysis published in July 2019 demonstrated that one-third (34%) of malpractice cases associated with death or disability resulted from an inaccurate or delayed diagnosis. This renders diagnostic error as the top cause of serious harm among medical errors.

What is the Diagnostic Process?

There are 2 paths a clinician may take in establishing a diagnosis.

The first of the two, which is known as the intuitive, or heuristic method, occurs when a (typically experienced) physician evaluates the patient’s presenting symptoms, the physical examination, diagnostic tests like imaging and blood test results, and engages in “pattern recognition.” Recognizing a pattern associated with the “illness script,” the clinician “matches” the script with a diagnosis based on both knowledge and previous experience.

The second method is more analytical and stepwise; it is more likely to be used by a less experienced clinician, or by any clinician when the illness script is not so easily recognized. This may occur when the reported symptoms are atypical, or when a patient presents with symptoms associated with a rare disease that the clinician has not previously encountered.

When employing this second method, the clinician uses a deliberate, iterative process in which she/he generates one or more possible differential diagnoses and tests these. In many cases, a combination of the two methods is employed; when used, this is called the “dual process method.” Research into diagnostic modalities is making it more and more clear that the dual process method- using both analytic and non-analytical processes- is associated with optimal practice.

When Are Diagnostic Errors Most Likely to Occur? The “Big Three”

Across practice settings, the misdiagnosis of vascular events, cancer, and infection have been called the “Big Three” and account for most of the morbidity and mortality attributable to diagnostic errors. The report estimates that 9.6% of patients in the United States with symptoms caused by major vascular events, infections, or cancers will be misdiagnosed. Within each of these major disease states, certain diagnoses, like stroke, sepsis, and lung cancer, are particularly prone to the possibility of diagnostic error. Misdiagnosis can occur in any clinical practice area. In the fast pace of the emergency department, however, where the clinician most likely does not know the patient- and the patient does not know the physician- misdiagnosis may be a particular risk.

How Can We Decrease Diagnostic Errors?

Although the document recognizes the role of system-level challenges that may contribute to diagnostic error (like lab reports that are not available until after the patient is discharged, lack of access to prompt specialist consultation), clearly the greatest responsibility for accurate diagnosis falls with the clinician. It is fundamental for clinicians to be aware of cognitive errors-those related to gaps in knowledge and to unconscious biases of various types that may contribute to flawed diagnostic-decision-making.

Diagnostic error is a complex issue; there is no one solution or magic bullet that alone can address the problem. Various strategies can are known to improve the quality of diagnostic decision making include: keeping up to date on the most current advances in medical knowledge (ideally based on an objective assessment of one’s individual learning needs and gaps), accessing second opinions as appropriate, use of validated clinical prediction tools when indicated, and importantly the use of a “diagnostic time out,” similar to a pause taken by the surgical team. This “diagnostic time out” may take on a structured form with a checklist of differential diagnoses, or may simply consist of a moment of structured reflection, before embarking on the plan of care. It is incumbent on our health systems that we establish processes- and create a supportive culture- in which clinicians can identify, will learn from, and hopefully reduce the risk of diagnostic errors and “near misses” in clinical practice.