Emergency Room diagnostic errors on Macro scale

People usually go to the Emergency Room (ER) when they think something is seriously wrong. Needless to say, a diagnostic error in the ER can result in serious harm, potentially death. A recent government study shows that this is happening on a Macro scale.

Diagnostic Errors in the Emergency Department: A Systematic Review

Agency for Healthcare Research and Quality, Department of Health & Human Services, Systematic Review, Dec 15, 2022

Although overall error and harm rates are derived from three smaller studies conducted outside the United States (in Canada, Spain, and Switzerland, with combined n=1,758), study methods were prospective and rigorous. All three were conducted at university hospitals, and, for the two studies used to estimate harms, about 92 percent of clinicians under study at those institutions had full training or formal certification in emergency medicine…

  • Overall diagnostic accuracy in the emergency department (ED) is high, but some patients receive an incorrect diagnosis (~5.7%). Some of these patients suffer an adverse event because of the incorrect diagnosis (~2.0%), and some of these adverse events are serious (~0.3%). This translates to about 1 in 18 ED patients receiving an incorrect diagnosis, 1 in 50 suffering an adverse event, and 1 in 350 suffering permanent disability or death. These rates are comparable to those seen in primary care and hospital inpatient care.

  • We estimate that among 130 million emergency department (ED) visits per year in the United States that 7.4 million (5.7%) patients are misdiagnosed, 2.6 million (2.0%) suffer an adverse event as a result, and about 370,000 (0.3%) suffer serious harms from diagnostic error.

Five conditions (#1 stroke, #2 myocardial infarction, #3 aortic aneurysm/dissection, #4 spinal cord compression/injury, #5 venous thromboembolism) account for 39 percent of serious misdiagnosis-related harms, and the top 15 conditions account for 68 percent.

Stroke, the top serious harm-producing disease, is missed an estimated 17% of the time. For a given disease, nonspecific or atypical symptoms increase the likelihood of error. For stroke, dizziness or vertigo increases the odds of misdiagnosis 14-fold over motor symptoms (those with dizziness and vertigo are missed initially 40% of the time)…

We identified 19,127 citations and included 279 studies.

The top 15 clinical conditions associated with serious misdiagnosis-related harms (accounting for 68% of serious harms) were
(1) stroke,
(2) myocardial infarction [heart attack],
(3) aortic aneurysm and dissection,
(4) spinal cord compression and injury,
(5) venous thromboembolism [blood clot in a vein],
(6/7 – tie) meningitis and encephalitis,
(6/7 – tie) sepsis ,
(8) lung cancer,
(9) traumatic brain injury and traumatic intracranial hemorrhage,
(10) arterial thromboembolism,
(11) spinal and intracranial abscess,
(12) cardiac arrhythmia,
(13) pneumonia,
(14) gastrointestinal perforation and rupture, and
(15) intestinal obstruction.

Average disease-specific error rates ranged from 1.5 percent (myocardial infarction) to 56 percent (spinal abscess), with additional variation by clinical presentation (e.g., missed stroke average 17%, but 4% for weakness and 40% for dizziness/vertigo)…

The strongest, most consistent predictors of ED diagnostic error were individual case factors that increased the cognitive challenge of identifying the underlying disorder, with nonspecific, mild, transient, or “atypical” symptoms being the most frequent…[end quote]

Doctors in the ER are rushed, like all doctors. They are trained to see “horses” not “zebras.” Diagnosing common presentations is easy. Diagnosing nonspecific, mild, transient, or “atypical” symptoms is hard, even if the disease would be readily recognized if presented with the usual symptoms.

Practical takeaways for METARs:

  1. Stroke is the deadliest and most frequently misdiagnosed. Add “dizziness” to the common list of stroke symptoms. Stroke must be diagnosed and treated during the “golden hour” to prevent brain damage. https://www.cdc.gov/stroke/signs_symptoms.htm

  2. An adult with a high fever and low blood pressure should suspect sepsis. Each year, according to the Centers for Disease Control and Prevention (CDC), at least 1.7 million adults in the U.S. develop sepsis, and nearly 270,000 die as a result.

  3. Some of these diseases kill slowly. (e.g. lung cancer). Others kill quickly (heart attack, stroke). There are often long lines in the ER so if you suspect a fast killer jump the line and scream “I think I’m having a heart attack! or stroke!” to get immediate attention.



From my professional experience, not always correct. During residency and while in private practice I’ve seen people come in for various non-serious reasons including boredom.

I wonder if they take into account evolving situations/changing presenting symptoms. I can remember one patient seen during residency training that was brought in for a fall. Highly intoxicated with an otherwise normal exam and labs. Diagnosis/plan: intoxicated - repeat blood alcohol until “normal” and can be discharge which by estimation formulas would be in 4-5 hours. About 30-40 minutes later, BP rising and heart rate falling and now has a changed neuro exam. Scan her head, brain bleed, off to surgery.

So would this count as a “misdiagnosis” in the studies accounting? If the cops had brought her in 30-40 minutes later, would have had different presenting symptoms? There are many times disease presentations evolve over time.


Jake Tapper, of CNN, and his wife share their story of how their daughter was misdiagnosed and her appendicitis went un-treated for several days.

Their tale is not one of revenge against the doctors, but of encouragement to parents and others to keep advocating for patients if you think something is wrong.