INTRODUCTION

Diagnostic errors are common and important causes of preventable morbidity and mortality in a variety of medical settings. Diagnostic errors leading to harm are most likely to involve diagnoses of cancer, vascular events, or infection. This topic focuses on approaches to measurement, etiologies, and interventions to decrease diagnostic error.

DEFINITIONS

Diagnostic process — The National Academies of Sciences, Engineering, and Medicine (NASEM) representation of the diagnostic process is the most widely accepted model (figure 1). The process begins with the patient's experience of a symptom or health condition and their engagement with the health care system, then enters a cyclical set of events in which clinicians gather, integrate, and interpret information to form a working diagnosis. The diagnostic process ends with the explanation of the health problem to the patient and management plan [1]. Whether patients respond as expected to a given treatment may inform the diagnostic process or lead to a return to diagnostic reasoning [2].

Diagnostic error — Diagnostic error is defined by the NASEM as the failure to either establish an accurate and timely explanation of the patient’s health problem(s) or communicate that explanation to the patient [1]. One challenge of the NASEM definition is that it can be difficult to ascertain if a diagnosis was “timely,” particularly in the emergency or inpatient setting where patients may evolve rapidly. In response, the diagnostic research community utilizes a variation on this definition. Diagnostic error is “a missed opportunity to make a timely or correct diagnosis, or take the next diagnostic action step, based on available evidence at the time” as a result of provider or system error [3]. Similar to other patient safety events, in which there may be an error that does not result in adverse event (eg, medication errors that do not result in an adverse drug event), both of these definitions recognize diagnostic error (missed, delayed, or wrong diagnosis) even in the absence of harm.

Because diagnosis is a process, it is important to note that not all changes in diagnosis are synonymous with error. Establishing the correct diagnosis may take time due to insufficient diagnostic information, atypical presentations, or clinical evolution (eg, a patient is eventually diagnosed with lupus but their presenting symptoms did not meet diagnostic criteria). A lengthy diagnostic process may be without process or outcome error.

Diagnostic adverse event — Diagnostic adverse event describes resultant patient harm from diagnostic error, typically due to a failure to treat or harm from treatment for a wrong diagnosis [4]. Malpractice studies indicate that diagnostic error is the most common cause of severe harm [5-7].