What’s New in the Patient Safety World

May 2013

Scope and Consequences of Diagnostic Errors



Diagnostic error has always lurked in the background of the patient safety movement. But in the past several years there has been a renewed focus on diagnostic error. Now researchers from Johns Hopkins have analyzed diagnosis-related claims from the National Practitioner Data Bank (NPDB) and the results are eye-opening (Tehrani 2013). They found that among malpractice claims, diagnostic errors appear to be the most common, most costly and most dangerous of medical mistakes. Diagnostic errors include failure to diagnose, wrong diagnosis, delayed diagnosis, failure to follow up on tests, etc.


Analyzing over 350,000 paid claims over a 25-year period they found diagnostic errors accounted for 28.6% of the claims, more than any other category. Moreover, they accounted for 35.2% of the total payments.


Diagnostic errors more often resulted in death than other categories of malpractice claims. Significantly, they also found that disability as a result of diagnostic error was substantial. The authors note that this means previous estimates of the impact of diagnostic errors were probably significant underestimates because they were based largely on autopsy studies. Outpatient diagnostic errors leading to claims were over twice as common as inpatient diagnostic errors, though the latter were more likely to lead to fatal outcomes.


What’s ironic is that we often don’t even know about our diagnostic errors unless there is a malpractice claim. Substantial periods of time typically elapse before it becomes apparent that a diagnostic error occurred. And it usually becomes apparent when the patient is elsewhere (another physician’s office, an emergency room, another hospital, etc.). An angry patient may call you and let you know about it but more often the patient simply loses confidence in you and just never returns to you for care. And if we don’t get feedback about our diagnostic errors or diagnostic accuracy we often get overconfident in our own abilities. And, of course, many of our diagnostic errors do not result in patient harm at all. However, they may result in delays and inconveniences.


In our April 2013 What’s New in the Patient Safety World column “AHRQ Recommended Patient Safety Practices” we noted the ten strategies identified by the AHRQ project that are "strongly encouraged" for adoption based on the strength and quality of evidence and twelve other strategies "encouraged" for adoption based on a slightly lesser strength and quality of evidence. Strategies targeted at diagnostic errors did not make the final list but the supplement with the evidence reviews (Annals of Internal Medicine 2013) did provide a systematic review of those strategies targeted at diagnostic errors (McDonald 2013). One is really struck by the paucity of good research on interventions to reduce diagnostic errors or at least identify them before they lead to patient harm or inconvenience.


Our March 2013 What’s New in the Patient Safety World column “Diagnostic Error in Primary Care” focused on a study using a trigger tool methodology to help identify diagnostic errors in primary care settings (Singh 2013). Singh and colleagues make several salient points about interventions to prevent diagnostic errors. First, given the wide variety of conditions and presenting symptoms they found in their study it is very unlikely that focusing solely on specific presentations will be successful in reducing overall errors. They note that most of the breakdowns occurred in the clinical encounter, perhaps with time pressures and short encounters contributing to inadequate decision making. Further yet they note that the trend toward team care and the patient-centered medical home may not result in the level of cognitive support needed for complex decision making. And the current levels of technological decision support for diagnosis are not readily available in most of today’s electronic medical records.


In our September 28, 2010 Patient Safety Tip of the Week “Diagnostic Error” we highlighted a review of diagnostic error by the Pennsylvania Patient Safety Authority. The PPSA review also provides a couple nice tools to help clinicians identify and avoid diagnostic errors. One is a chart audit tool to help identify errors adopted from the article by Schiff et al (Schiff 2009). The other is a simple checklist the clinician can use to help focus the things he/she needs to do to in each case avoid diagnostic errors.


We hope you’ll look at some of our prior columns on diagnostic error, listed below, that highlight some of the work by some excellent researchers (like Mark Graber, Pat Croskerry, John Ely, Gordon Schiff, Hardeep Singh, Jerry Groopman, Gary Klein and many others) on the way clinicians think and the cognitive biases that are important in diagnostic errors. Now that these recent studies have identified the scope of the problem it is time to begin focusing on ways to mitigate the problem.




Some of our prior Patient Safety Tips of the Week on diagnostic error:

·        September 28, 2010     Diagnostic Error

·        November 29, 2011     More on Diagnostic Error

·        May 15, 2012              Diagnostic Error Chapter 3

·        May 29, 2008             If You Do RCA’s or Design Healthcare Processes…Read Gary Klein’s Work

·        August 12, 2008           Jerome Groopman’s “How Doctors Think”

·        August 10, 2010           It’s Not Always About The Evidence

·        January 24, 2012          Patient Safety in Ambulatory Care

·        October 9, 2012          Call for Focus on Diagnostic Errors

·        March 2013                  Diagnostic Error in Primary Care

·        And our review of Malcolm Gladwell’s “Blink” in our Patient Safety Library








Tehrani ASS, Lee HW, Mathews SC, et al. 25-Year summary of US malpractice claims for diagnostic errors 1986–2010: an analysis from the National Practitioner Data Bank

BMJ Qual Saf 2013; Published online 22 April 2013 doi:10.1136/bmjqs-2012-001550




Annals of Internal Medicine. Making Health Care Safer: A Critical Review of Evidence Supporting Strategies to Improve Patient Safety. Annals of Internal Medicine 2013; 158(5_Part_2)




McDonald KM, Matesic B, Contopoulos-Ioannidis DG, et al. Patient Safety Strategies Targeted at Diagnostic Errors: A Systematic Review. Ann Intern Med 2013; 158(5_Part_2): 381-389




Singh H, Giardina TD, Meyer AND, et al. Types and Origins of Diagnostic Errors in Primary Care Settings. JAMA Intern Med 2013; published online February 25, 2013




Pennsylvania Patient Safety Authority (PPSA). Diagnostic Error in Acute Care. Pa Patient Saf Advis 2010 Sep;7(3):76-86




Schiff GD, Hasan O, Kim S; et al. Diagnostic Error in Medicine: Analysis of 583 Physician-Reported Errors. Arch Intern Med, Nov 2009; 169: 1881 – 1887




DEER Taxonomy Chart Audit Tool




Pennsylvania Patient Safety Authority. A Physician Checklist for Diagnosis.







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