Diagnostic errors are among the most serious and least visible patient safety problems in medicine. Over the past decade, researchers have tried both to measure how often they happen and to test ways to prevent them. The most recent large estimate, published in BMJ Quality & Safety in 2023 by a team led by researchers at Johns Hopkins, concluded that about 795,000 Americans die or are permanently disabled each year because of diagnostic error.
This post first ran in March 2018. At the time, it said that new studies were looking at the causes of diagnostic errors, but it did not name a particular study. We have updated it to identify and date the research that has shaped the field, to explain what that research suggests about reducing errors, and to describe what patients can do. When a missed or delayed diagnosis does cause harm, the Houston medical malpractice attorneys at Davis & Davis help patients and families evaluate whether a failure to diagnose claim exists under Texas law.
How Researchers Have Measured Diagnostic Error
Diagnostic error is hard to count, because a missed diagnosis often leaves no obvious trace in the record. Several estimates have been widely cited over the years, each using a different method:
- 2002, hospital deaths: Drawing on autopsy studies, patient safety researchers Lucian Leape, Donald Berwick, and David Bates estimated in JAMA that diagnostic errors may account for 40,000 to 80,000 hospital deaths a year in the United States. This was the figure the original version of this post cited.
- 2014, outpatient care: A study in BMJ Quality & Safety by Hardeep Singh and colleagues estimated that about 5 percent of U.S. adults, roughly 12 million people a year, experience a diagnostic error in outpatient care, and that about half of those errors could be harmful. We wrote about that study in our post on how millions of Americans are misdiagnosed.
- 2015, national report: The National Academies of Sciences, Engineering, and Medicine published Improving Diagnosis in Health Care, which defined diagnostic error as a failure to establish an accurate and timely explanation of a patient’s health problem or to communicate that explanation to the patient.
- 2023, serious harms: The Johns Hopkins-led study estimated 371,000 deaths and 424,000 permanent disabilities a year across all clinical settings, a total of about 795,000. The authors noted that cutting diagnostic errors in half for stroke, sepsis, pneumonia, pulmonary embolism, and lung cancer could prevent about 150,000 of those harms each year.
These figures are modeled estimates rather than direct counts, and researchers continue to debate the methods. Taken together, they show that diagnostic error is common enough that most patients and families should know how it happens and how to reduce the risk.
Why Diagnostic Errors Happen
The original version of this post pointed to several causes that still appear throughout the research. Doctors and nurses often see a high volume of patients, which limits the time spent with each one. Diagnostic methods are not always standardized, so the process can vary from one hospital or clinic to the next. Communication in fast-paced settings can break down, so a diagnosis may rest on incomplete or inaccurate information, or a test result may never reach the person who needs to act on it.
The National Academies report described diagnosis as a team process involving clinicians, patients, and families, and it treated errors as the product of both thinking errors and system problems. A clinician may settle too early on one explanation, for example, while a system may fail to flag an abnormal result. Our article on how a differential diagnosis works explains the reasoning process doctors are trained to use to avoid premature conclusions.
What Research Suggests Can Reduce Errors
The National Academies report set out eight goals for improving diagnosis. The first was to facilitate more effective teamwork in the diagnostic process among healthcare professionals, patients, and their families. The others included better education and training, health information technology that supports patients and clinicians, systems for identifying and learning from diagnostic errors, a work culture that supports diagnosis, changes to reporting and liability systems, payment and care delivery designs that support diagnosis, and dedicated research funding.
In practice, efforts to reduce errors have focused on a few recurring themes. Hospitals and clinics have worked on tracking abnormal test results so that they are not lost between providers. Second reviews of imaging and pathology are used in some settings. Researchers have studied checklists and structured pauses that prompt clinicians to ask what else a patient’s symptoms could mean, with mixed results. Newer tools, including artificial intelligence, are being tested to support diagnosis, though they bring their own risks, as our article on AI misdiagnosis and liability explains.
What Patients Can Do
Because the research treats patients and families as part of the diagnostic team, there are practical steps you can take. Give your doctor a complete history, including all medications and any symptoms that seem unrelated. Ask what else could explain your symptoms and what the next step is if the first treatment does not work. Do not assume that no news about a test means a normal result; ask when and how you will get results, and follow up if you do not hear back. If your symptoms continue or worsen, or a diagnosis does not seem to fit, consider a second opinion. Our post on how often doctors fail to diagnose illnesses lists the conditions most often affected.
When a Diagnostic Error Becomes a Legal Claim
Not every diagnostic error is malpractice. Medicine involves uncertainty, and some conditions are genuinely hard to identify. A claim generally requires showing that the provider failed to do what a reasonably careful provider in the same field would have done under the same circumstances, such as ordering an appropriate test, following up on an abnormal result, or making a needed referral, and that the failure caused harm that a timely diagnosis would likely have prevented.
In Texas, these cases are health care liability claims under Chapter 74 of the Civil Practice and Remedies Code. A claim generally must be filed within two years from the date of the breach or from the date the related course of treatment or hospitalization ended, and Texas does not apply a general discovery rule. The claimant must give written notice at least 60 days before filing suit, which tolls the deadline for 75 days, and must serve a report from a qualified medical professional within 120 days after each defendant files an answer.
Talk With Davis & Davis About a Missed or Delayed Diagnosis
Our firm focuses on medical malpractice, including claims arising from missed and delayed diagnoses. We review medical records, test results, and the timeline of care with qualified medical professionals to determine whether the care met accepted standards. Every case is different, and we cannot promise a particular result.
If you believe a diagnostic error harmed you or a family member, contact Davis & Davis to request a free consultation and learn more about your options.
Frequently Asked Questions About Diagnostic Error Research
How many people are harmed by diagnostic errors each year?
A 2023 study in BMJ Quality and Safety estimated that about 795,000 Americans die or are permanently disabled each year because of diagnostic error, including about 371,000 deaths. A 2014 study estimated that about 12 million U.S. adults a year experience a diagnostic error in outpatient care. Both figures are modeled estimates.
Why do diagnostic errors happen?
Research points to a mix of thinking errors and system problems. Examples include settling too early on one explanation, not ordering an appropriate test, test results that never reach the right person, limited time with patients, and incomplete information about the patient’s history.
What can I do to lower my risk of a misdiagnosis?
Share a complete history and medication list, ask what else could explain your symptoms, find out when and how you will get test results and follow up if you do not hear back, and consider a second opinion if your symptoms continue or the diagnosis does not seem to fit.
Is every misdiagnosis medical malpractice?
No. A misdiagnosis becomes malpractice when the provider failed to meet the standard of care that a reasonably careful provider would have met, and that failure caused harm a timely diagnosis would likely have prevented. A review of the records by a qualified medical professional is usually needed to answer that question.
How long do I have to file a misdiagnosis claim in Texas?
Generally two years under Texas Civil Practice and Remedies Code section 74.251, measured from the date of the breach or the end of the related treatment rather than from when you discovered the error. Written notice to the provider tolls the deadline for 75 days, and the rules are strictly applied, so it is best to speak with an attorney promptly.
