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Minimizing Diagnostic Error in Health Care: Ten Things You Could Do Tomorrow



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Inside MedicalLiability
Compliance, Quality,
and MPL—The
Look AgainWhat
Do You Really See?
Useful Tips for Avoiding
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Mark L. Graber, MD, FACP, is a Senior Fellow, RTI International; Professor Emeritus, SUNY Stony Brook
School of Medicine; and Founder and President, Society to Improve Diagnosis in Medicine;
Lists for physicians,patients,and
healthcare organizations
Error: 10 Things
You Could Do
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Diagnostic error gets short shrift
In a recent article, I and two of my colleagues noted the dearth of
attention paid to delayed, missed, and incorrect diagnosis:
“Diagnosis apparently gets overlooked in most efforts to ensure
quality and safety.1Tellingly, in the 1998 Institute of Medicine
repor t, To Err Is Human, the term “medication error” was men-
tioned 70 times, while “diagnostic error” appeared only twice. Yet,
in 2002 Lucien Leape et al.2estimated from autopsy data that diag-
nostic errors were responsible for some 40,000 to 80,000 deaths every
year. More recently, estimates of the diagnostic error rate in ambulato-
ry practice suggest that one out of every 1,000 diagnostic encounters
results in harm from a diagnostic error.2 Applying these figures to the
average-sized hospital suggests that diagnostic error will harm one
patient every day in ambulatory care, and be responsible for five to ten
patient deaths per year.
Despite these figures, and the voluminous data on the promi-
Despite its obvious importance, diagnostic error has to a great extent been ignored in the
world of patient safety. Strategies for finding the actual incidence of misdiagnosis, and
beyond that, the diverse sorts of cognitive and procedural blind spots that cause it, are
still in their relative infancy. But in the last few years, data is starting to emerge. After
first reviewing these findings, I offer some practical tips on how physician practices and
healthcare systems can minimize the likelihood of misdiagnosis. Note that there are dif-
ferent considerations here for each of the parties involved: patients, their physicians,
and healthcare organizations.
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nence of diagnostic error in medical professional liability (MPL)
claims, physicians seem somehow to think that such errors are in fact
the problem for the other fellow, physicians less careful or less well
trained. How can we explain this yawning discrepancy between the
estimated rate of diagnostic error (10% of diagnoses are wrong,
according to best estimates), and the physician’s perception that the
quality of their care is excellent? First, the vast majority of diagnostic
errors, fortunately for all concerned, don’t result in harm. The error is
inconsequential, or is caught, or harm is mitigated. Secondly, diagnosis
plays out over time and over different healthcare settings. A diagnostic
error might not be appreciated until later on, further on down the line.
Third, the culture of medicine is such that physicians are reluctant to
notify upstream colleagues that the diagnosis
changed. And finally, the odds of a truly cata-
strophic outcome are rare—using the figures
provided above, the average busy physician
might be involved in just one or two cases of
fatal error over a lifetime of practice, and may
never learn about these cases even if they occur.
Let’s also acknowledge that physicians
actually do a remarkable job with diagnosis, given
the fact that there are more than 10,000 diseases,
and that the presentations of these disease are
typically nonspecific.
Solid numbers on prevalence
Determining the actual incidence of diagnostic
error has proved to be a daunting task. And yet
this information is essential for any studies that
seek to understand it. The current estimates of
the diagnostic error rate derive from several dif-
ferent types of research approaches, each with its
advantages and its corresponding limitations as
well. 3
Data from autopsies are considered the
“gold standard”; they furnish precise informa-
tion on the discrepancy between inpatient diag-
nosis and postmortem findings. However,
autopsies are increasingly rare in the U.S. Other
researchers have used surveys, of both patients
and doctors, to elicit information on errors in
diagnosis. Roughly half of physicians, in such
surveys, have said that they encounter diagnostic
errors nearly once a month. The use of stan-
dardized patients—real or simulated patients
assuming the classical symptoms of diseases
commonly encountered—makes it possible,
because so many elements are controlled, for
researchers to delve into the cognitive and other
factors that may hinder the process of achieving
a correct diagnosis. Diagnostic error rates in
such studies are in the range of 10% – 15%.
Data from closed claims are important
resources for learning about misdiagnosis.
PIAAs Data Sharing Project (DSP) currently
holds more than 260,000 claims, and problems
related to diagnostic error are the most common
Among the top five chief medical factors by closed claims, diagnostic error
ranked second and resulted in the highest average indemnity payment.
Among the top five medical specialties for claims involving diagnostic
error by closed claims, radiologists ranked first and Ob/Gyns resulted in
the highest average indemnity payment.
From Inside the PIAA Data Sharing Project….
These two figures show some statistically robust numbers on the critical
importance of misdiagnosis in the medical professional liability arena.
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allegation cited in lawsuits, just as in every other large medical profes-
sional liability claims database in the U.S. In these claims, both the
final diagnosis and the diagnosis made by the treating physician are
explicitly identified. (See page 24 for more detailed information about
what is revealed via the DSP, in regard to diagnostic error.)
Some promising new approaches to measuring the incidence of
diagnostic error include “trigger tools” (EHRs provide alerts on cases
at high risk of diagnostic error) and asking physicians and patients to
report any errors they see, voluntarily.2,4
When do errors occur?
In one such study, researchers investigated 190 unique instances of
diagnostic errors that were picked up via two trigger queries: one
linked with a hospital stay that happened within 14 days after a pri-
mary care visit, and the other specifying an emergency department,
urgent care, or second primary care visit, again 14 days or less after the
original visit.2Most of the diagnoses missed were of common condi-
tions, like asthma, pneumonia, and anemia. Several other studies have
confirmed this finding—it’s not rare diseases causing most problems,
it’s the common ones.5Of particular interest are the chief presenting
symptoms implicated in cases of diagnostic error, and again its the
common complaints that top the list: cough, abdominal pain, short-
ness of breath, and back and chest pain. The authors comment that of
the conditions linked with diagnostic errors, “these conditions were
highly variable and sometimes did not bear any obvious direct rela-
tionship to the condition that was missed. Notably, the cases of diag-
nostic error in MPL claim series involve missed or delayed diagnosis of
cancer or cardiovascular conditions.
Most diagnostic errors involve a breakdown in the sequential
diagnostic processes involving a patient and the physician. In the
series just quoted by Singh et al., errors were linked with taking a
patient history (56.3%), examination (47.4%), and/or the ordering of
tests for making a diagnosis. Similar findings are reported by Gordon
Schiff and colleagues.6Using a different analytical framework, in the
cases I’ve studied, the “synthesis” phase of diagnosis seemed to be the
most problematic, putting all the information together to arrive at the
most likely diagnosis.7
Cognitive and system errors
The various errors in cognitive thinking that may arise in the process
of diagnosis have been fairly well studied by now. Hindsight bias was
the subject of a recent article in Inside Medical Liability (Dr. Pierre
Campbell, “I Knew It All Along, Third Quarter 2013, page 46). Along
with framing effects, context errors, and premature closure, this is one
of the common cognitive shortcomings that can lead to diagnostic
error. There is obviously much work left to be done in figuring out the
mental habits, possible prejudices, predilections, and processes
involved in the clinical reasoning process. System-related flaws are
equally likely to contribute to diagnostic error. The leading factors in
this category include suboptimal communication or care coordination,
access issues (including access to appropriate expertise on a timely
basis), trainee supervision, and a host of “human factor” issues that
detract from diagnosis: time pressures, excess workload, distractions,
clumsy EMRs, etc.
What can be done?
Although a host of interventions have been proposed that might
improve diagnostic reliability, research in this area is just beginning.
Promising approaches include better use of electronic medical records
and diagnosis-related decision support systems, reflective practice, and
taking advantage of second opinions. Patients can also play an impor-
tant role in improving diagnostic reliability, and should be encouraged
to play an active role in this process. Finally, our healthcare practices
and organizations set the stage that influences our ability to diagnose
reliably. Suggestions for each of these parties are included the
following page.
Let’s also acknowledge that physicians actually do a remarkable job with diagnosis, given the fact that
there are more than 10,000 diseases, and that the presentations of these disease are typically nonspecific.
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1. Leape L, Berwick D, Bates D. Counting deaths from medical errors. JAMA.
2002 288(19):2405.
2. Singh H et al. Types and origins of diagnostic errors in primary care set-
tings. JAMA Intern Med. 2013 173(6):418-425.
3. Graber M. The incidence of diagnostic error in medicine. BMJ Qual Safety,
4. Trowbridge R, Salvador O. Addressing diagnostic errors: An institutional
approach. Focus on Patient Safety--A Newsletter from the National Patient
Safety Foundation. 2010 13(3):1-5.
5. Gandhi TK et al. Missed and delayed diagnoses in the ambulatory setting: a
study of closed malpractice claims. Ann Intern Med. 2006 145(7):488-96.
6. Schiff G.D. et al. Diagnostic error in medicine: analysis of 583 physician-
reported errors. Arch Intern Med. 2009 169(20):1881-7.
7. Graber ML, Franklin N, Gordon RR. Diagnostic error in internal medicine.
Arch Intern Med. 2005 165:1493-1499.
Note that some of the material in this article may be published simultaneously
by the National Patient Safety Foundation in recognition of Patient Safety
Awareness Week, 2014.
For related information, see
1. Be reflective. Take a diag-
nostic “time out.”
2. Listen, really listen, to your
patients and their caregivers.
3. Learn the causes of cognitive
error and how to avoid pitfalls.
4. Don’t trust your intuition.
Always construct a differential
5. Take advantage of second
6. Use diagnosis-specific deci-
sion support resources: DXplain,
Isabel, VisualDx, checklists.
7. Make the patient your part-
ner in diagnosis: Ensure they
know how to get back to you if
symptoms change or persist.
8. Ensure all ordered diagnostic
tests and consults are completed
and that you know the results.
Designate a surrogate to review
test results if you aplan to be
9. Speak directly with the staff
providing you with diagnostic test
results: radiologists, pathologists,
clinical pathologists. If you aren’t
sure of the most appropriate diag-
nostic strategy, ask, or use online
test-ordering advice.
10. Empower your colleagues to
let you know if they become
aware that a diagnosis you made
has changed.
1. Identify diagnostic errors:
follow up with patients recently
seen in the ER. Encourage inpa-
tient attendings to report errors.
2. Provide clinicians with diag-
nosis-specific decision-support
tools: DXplain, Isabel, VisualDX,
3. Identify physician volunteers
interested in providing second
opinions and advertise their
services to patients and their
physician peers.
4. Ensure there is radiology
coverage on WHEN tours to read
stat films.
5. Close the loop on diagnostic
test results. Send results to
patients. Monitor how many crit-
ical test results are acted upon
within 30 days.
6. Ensure that providers on
vacation have designated a sur-
rogate to review test results.
7. Encourage accurate problem
lists, and a differential diagnosis.
8. Establish ways for providers
to receive feedback on their
9. Encourage autopsies or
10. Ensure senior clinicians
review all new cases with
trainees in real time.
11. Encourage and facilitate
communication between front-
line clinicians and physician staff
in radiology and the clinical
12. Use root cause analysis to
identify remediable system-relat-
ed contributions to diagnostic
error; host “Morbidity and
Mortality” conferences with staff
to review these cases.
13. Empower nurses to become
involved in improving diagnosis.
Monitor for new or resolving
symptoms, ensure tests get
done, facilitate communication
between patients and providers.
14. Empower patients to be
proactive in their care, to take
advantage of second opinions,
and to provide feedback on diag-
nostic errors.
Steps healthcare organizations can take to avoid diagnostic errors
1. Be a good historian. Keep
records of your symptoms, when
they started, and how they have
responded (or not) to treatment.
2. Take advantage of cancer
3. Make sure you know your
test results and keep accurate
records of these results. Don’t
assume no news is good news.
Follow up if you don’t receive
copies or the results of tests and
4. SPEAK UP! Ask:
a. What else could it be?
b. What should I expect?
c. When and how should I fol-
low up if symptoms persist or
d. What resources can I use to
learn more?
e. Is this test worthwhile?
Can we wait? (More testing does
not always mean better care!)
5. Don’t assume the healthcare
system will adequately coordi-
nate your care. Keep your own
records, and help coordinate
your own care.
6. Provide feedback about
diagnostic errors to providers
and organizations.
7. Understand that diagnosis
always involves some element of
8. Get a second opinion regard-
ing serious diagnoses or unre-
solved symptoms.
9. Take advantage of help and
support: Support groups, patient
safety staff, patient advocates.
Steps patients can take to avoid diagnostic errors
Steps physicians can take to avoid diagnostic errors
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... The tool provides a web application or form for patients to list their medications, warning signs, test results and recommendations. By preparing well before a medical appointment, patients will be more comfortable asserting themselves and asking questions such as, "What else could this be?", one of the universal antidotes to prevent diagnostic errors [15]. ...
... The tool provides a web application or form for patients to list their medications, warning signs, test results and recommendations. By preparing well before a medical appointment, patients will be more comfortable asserting themselves and asking questions such as, "What else could this be?", one of the universal antidotes to prevent diagnostic errors [15]. ...
Full-text available
The National Academy of Medicine (NAM) in the recently issued report Improving Diagnosis in Health Care outlined eight major recommendations to improve the quality and safety of diagnosis. The #1 recommendation was to improve teamwork in the diagnostic process. This is a major departure from the classical approach, where the physician is solely responsible for diagnosis. In the new, patient-centric vision, the core team encompasses the patient, the physician and the associated nursing staff, with each playing an active role in the process. The expanded diagnostic team includes pathologists, radiologists, allied health professionals, medical librarians, and others. We review the roles that each of these team members will need to assume, and suggest “first steps” that each new team member can take to achieve this new dynamic.
Full-text available
The goal of this study was to determine the relative contribution of system-related and cognitive components to diagnostic error and to develop a comprehensive working taxonomy. One hundred cases of diagnostic error involving internists were identified through autopsy discrepancies, quality assurance activities, and voluntary reports. Each case was evaluated to identify system-related and cognitive factors underlying error using record reviews and, if possible, provider interviews. Ninety cases involved injury, including 33 deaths. The underlying contributions to error fell into 3 natural categories: "no fault," system-related, and cognitive. Seven cases reflected no-fault errors alone. In the remaining 93 cases, we identified 548 different system-related or cognitive factors (5.9 per case). System-related factors contributed to the diagnostic error in 65% of the cases and cognitive factors in 74%. The most common system-related factors involved problems with policies and procedures, inefficient processes, teamwork, and communication. The most common cognitive problems involved faulty synthesis. Premature closure, ie, the failure to continue considering reasonable alternatives after an initial diagnosis was reached, was the single most common cause. Other common causes included faulty context generation, misjudging the salience of findings, faulty perception, and errors arising from the use of heuristics. Faulty or inadequate knowledge was uncommon. Diagnostic error is commonly multifactorial in origin, typically involving both system-related and cognitive factors. The results identify the dominant problems that should be targeted for additional research and early reduction; they also further the development of a comprehensive taxonomy for classifying diagnostic errors.
Full-text available
A wide variety of research studies suggest that breakdowns in the diagnostic process result in a staggering toll of harm and patient deaths. These include autopsy studies, case reviews, surveys of patient and physicians, voluntary reporting systems, using standardised patients, second reviews, diagnostic testing audits and closed claims reviews. Although these different approaches provide important information and unique insights regarding diagnostic errors, each has limitations and none is well suited to establishing the incidence of diagnostic error in actual practice, or the aggregate rate of error and harm. We argue that being able to measure the incidence of diagnostic error is essential to enable research studies on diagnostic error, and to initiate quality improvement projects aimed at reducing the risk of error and harm. Three approaches appear most promising in this regard: (1) using 'trigger tools' to identify from electronic health records cases at high risk for diagnostic error; (2) using standardised patients (secret shoppers) to study the rate of error in practice; (3) encouraging both patients and physicians to voluntarily report errors they encounter, and facilitating this process.
Full-text available
Importance Diagnostic errors are an understudied aspect of ambulatory patient safety. Objectives To determine the types of diseases missed and the diagnostic processes involved in cases of confirmed diagnostic errors in primary care settings and to determine whether record reviews could shed light on potential contributory factors to inform future interventions. Design We reviewed medical records of diagnostic errors detected at 2 sites through electronic health record–based triggers. Triggers were based on patterns of patients' unexpected return visits after an initial primary care index visit. Setting A large urban Veterans Affairs facility and a large integrated private health care system. Participants Our study focused on 190 unique instances of diagnostic errors detected in primary care visits between October 1, 2006, and September 30, 2007. Main Outcome Measures Through medical record reviews, we collected data on presenting symptoms at the index visit, types of diagnoses missed, process breakdowns, potential contributory factors, and potential for harm from errors. Results In 190 cases, a total of 68 unique diagnoses were missed. Most missed diagnoses were common conditions in primary care, with pneumonia (6.7%), decompensated congestive heart failure (5.7%), acute renal failure (5.3%), cancer (primary) (5.3%), and urinary tract infection or pyelonephritis (4.8%) being most common. Process breakdowns most frequently involved the patient-practitioner clinical encounter (78.9%) but were also related to referrals (19.5%), patient-related factors (16.3%), follow-up and tracking of diagnostic information (14.7%), and performance and interpretation of diagnostic tests (13.7%). A total of 43.7% of cases involved more than one of these processes. Patient-practitioner encounter breakdowns were primarily related to problems with history-taking (56.3%), examination (47.4%), and/or ordering diagnostic tests for further workup (57.4%). Most errors were associated with potential for moderate to severe harm. Conclusions and Relevance Diagnostic errors identified in our study involved a large variety of common diseases and had significant potential for harm. Most errors were related to process breakdowns in the patient-practitioner clinical encounter. Preventive interventions should target common contributory factors across diagnoses, especially those that involve data gathering and synthesis in the patient-practitioner encounter.
Full-text available
Missed or delayed diagnoses are a common but understudied area in patient safety research. To better understand the types, causes, and prevention of such errors, we surveyed clinicians to solicit perceived cases of missed and delayed diagnoses. A 6-item written survey was administered at 20 grand rounds presentations across the United States and by mail at 2 collaborating institutions. Respondents were asked to report 3 cases of diagnostic errors and to describe their perceived causes, seriousness, and frequency. A total of 669 cases were reported by 310 clinicians from 22 institutions. After cases without diagnostic errors or lacking sufficient details were excluded, 583 remained. Of these, 162 errors (28%) were rated as major, 241 (41%) as moderate, and 180 (31%) as minor or insignificant. The most common missed or delayed diagnoses were pulmonary embolism (26 cases [4.5% of total]), drug reactions or overdose (26 cases [4.5%]), lung cancer (23 cases [3.9%]), colorectal cancer (19 cases [3.3%]), acute coronary syndrome (18 cases [3.1%]), breast cancer (18 cases [3.1%]), and stroke (15 cases [2.6%]). Errors occurred most frequently in the testing phase (failure to order, report, and follow-up laboratory results) (44%), followed by clinician assessment errors (failure to consider and overweighing competing diagnosis) (32%), history taking (10%), physical examination (10%), and referral or consultation errors and delays (3%). Physicians readily recalled multiple cases of diagnostic errors and were willing to share their experiences. Using a new taxonomy tool and aggregating cases by diagnosis and error type revealed patterns of diagnostic failures that suggested areas for improvement. Systematic solicitation and analysis of such errors can identify potential preventive strategies.
Design: Retrospective review of 307 closed malpractice claims in which patients alleged a missed or delayed diagnosis in the ambulatory setting. Setting: 4 malpractice insurance companies. Measurements: Diagnostic errors associated with adverse outcomes for patients, process breakdowns, and contributing factors. Results: A total of 181 claims (59%) involved diagnostic errors that harmed patients. Fifty-nine percent (106 of 181) of these errors were associated with serious harm, and 30% (55 of 181) resulted in death. For 59% (106 of 181) of the errors, cancer was the diagnosis involved, chiefly breast (44 claims [24%]) and colorectal (13 claims [7%]) cancer. The most common breakdowns in the diagnostic process were failure to order an appropriate diagnostic test (100 of 181 [55%]), failure to create a proper follow-up plan (81 of 181 [45%]), failure to obtain an adequate history or perform an adequate physical examination (76 of 181 [42%]), and incorrect interpretation of diagnostic tests (67 of 181 [37%]). The leading factors that contributed to the errors were failures in judgment (143 of 181 [79%]), vigilance or memory (106 of 181 [59%]), knowledge (86 of 181 [48%]), patient-related factors (84 of 181 [46%]), and handoffs (36 of 181 [20%]). The median number of process breakdowns and contributing factors per error was 3 for both (interquartile range, 2 to 4). Limitations: Reviewers were not blinded to the litigation outcomes, and the reliability of the error determination was moderate. Conclusions: Diagnostic errors that harm patients are typically the result of multiple breakdowns and individual and system factors. Awareness of the most common types of breakdowns and factors could help efforts to identify and prioritize strategies to prevent diagnostic errors.
In Reply: Dr Gabel cautions that the reduction in overall anesthetic mortality may be less than we quoted for anesthesia in low risk patients, although the figure he cites, 1 in 15 000, is also 90% lower than the rate found in the 1950s.1 This progress in anesthesia mortality is even more remarkable, given that patients undergoing anesthesia today are older, have more comorbid conditions, and are receiving riskier and more complicated operations than before. Another measure of improvement is the dramatic decline in anesthetists' malpractice insurance rates.2 Anesthesia remains a powerful example of what can be accomplished by focusing on safety.
Addressing diagnostic errors: An institutional approach. Focus on Patient Safety--A Newsletter from the National Patient Safety Foundation
  • R Trowbridge
  • O Salvador
Trowbridge R, Salvador O. Addressing diagnostic errors: An institutional approach. Focus on Patient Safety--A Newsletter from the National Patient Safety Foundation. 2010 13(3):1-5.