Patient Safety Topics
Diagnostic Error

Diagnosis involves a complex system with many team members and numerous interdependent steps, all of which can make it challenging to identify and learn from failures in the process. The Pennsylvania Patient Safety Authority discussed reported events involving patient harm, as well as other aspects of how diagnosis is involved in nearly every healthcare encounter, in an October 2018 supplement to the Pennsylvania Patient Safety Advisory.

Key Data and Statistics

A query of the Pennsylvania Patient Safety Reporting System database for Serious Events likely to involve diagnostic error or the diagnostic process reported during calendar year 2016 yielded 1,212 event reports, from which the Authority identified 138 diagnostic process failure events. The Authority modified the diagnostic error evaluation and research (DEER) taxonomy and classified events according to process step and failure point. In the event reports, failure points in testing were involved most frequently (68.1%, n = 94 of 138) and the surgical/procedural care area predominated (21.0%, n = 29 of 138). Although the monitoring/follow-up process step accounted for just 13.0% of all events, it represented nearly half of those that resulted in death.

Figure 1. Percentage of Diagnostic Process Failure Events by Process Step (N =138) 

Table 2. PA-PSRS Event Narrative Examples


Excerpted from: Jones R, Magee MC. Identifying and learning from events involving diagnostic error: it’s a process . Pa Patient Saf Advis 2018 Oct 31 [cited 2018 Oct 31].

Educational Tools

Modified DEER Taxonomy
This adapted taxonomy may be used to classify where a failure occurred during the diagnostic process.

Diagnostic Error Measures Worksheet
This sample worksheet may be used for documenting facility-specific process and outcome measures involving physician misdiagnosis.

Patient Education Regarding Diagnostic Error
This sample handout is intended to help healthcare providers encourage patients to be active participants in each and every physician encounter.

Pennsylvania Diagnostic Error in Acute Care

This research poster illustrates common causes of diagnostic errors reported in Pennsylvania, select outcome and process measures to identify errors in individual facilities, and stategies to prevent these errors.

This pocket resource for physicians includes a general checklist designed to minimize diagnostic error.

A poster geared towards patients being an active part of their diagnosis.
A poster geared towards healthcare workers and the diagnostic process.

​In the spring of 2018, the Authority convened an expert panel of 10 speakers to discuss issues in diagnostic error and strategies for improvement.  


Safety Tips for Patients



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