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New Report Finds Diagnostic Errors Harm ‘Unacceptable Number’ of Patients

Health Letter, December 2015

By Michael Carome, M.D.

Receiving the right diagnosis is a critical aspect of any patient’s medical care. When physicians and other health care providers fail to make accurate and timely diagnoses, they place their patients at risk of serious harm.

In September, the prestigious Institute of Medicine (IOM) issued a comprehensive report that identified diagnostic errors as a persistent and pervasive problem.[1] The report, titled Improving Diagnosis in Health Care, bluntly characterized such errors as a decadeslong “blind spot” within the U.S. health care system that “continue[s] to harm an unacceptable number of patients.” Indeed, each year one out of 20 adults receiving outpatient care in the U.S. experiences a diagnostic error.

To address this staggering problem, the report authors offer a litany of recommendations, most of which would take years to implement.

Defining diagnostic errors

According to the IOM report, a diagnostic error involves any of the following three circumstances:

  • An inaccurate diagnosis;
  • An untimely diagnosis; or
  • A failure to communicate a diagnosis to the patient.

An inaccurate diagnosis is the most easily recognized type of diagnostic error. One example would be diagnosing a patient’s abdominal pain as a stomach ulcer when they actually have pancreatic cancer.

A diagnosis is untimely when it is meaningfully delayed. These errors can be more difficult to identify because the definition of timeliness depends on context. For example, if a patient goes to the emergency room complaining of acute chest pain and shortness of breath, reaching an accurate diagnosis within minutes or hours would be considered timely. For other circumstances, making a diagnosis in weeks or months may be considered timely.

Finally, an accurate and timely diagnosis cannot benefit a patient unless it is effectively communicated to the patient (or the patient’s health care decision-maker). Without accurate, complete information, the patient is unable to consider and pursue appropriate treatment options.

Possible harms

The authors of the IOM report conducted a comprehensive review of the scientific literature in an attempt to understand the frequency, severity and impact of diagnostic errors. They found that the problem is both widespread and long-standing, as evidenced by the following statistics highlighted in the IOM report:

  • “A conservative estimate found that 5 percent of U.S. adults who seek outpatient care each year experience a diagnostic error.”
  • “[Autopsy] research spanning decades has shown that diagnostic errors contribute to approximately 10 percent of patient deaths.”
  • “Medical record reviews suggest that diagnostic errors account for 6 to 17 percent of hospital adverse events.”
  • “Diagnostic errors are the leading type of paid medical malpractice claims, are almost twice as likely to have resulted in the patient’s death compared to other claims, and represent the highest proportion of total payments.”

The authors concluded that “most people will experience at least one diagnostic error in their lifetime, sometimes with devastating consequences.”

Diagnostic errors can cause serious physical harm, including death, through two basic pathways: by a delay in appropriate treatment for a serious disease, or by provision of unnecessary, harmful treatments. Consider a patient complaining of chest pain who is diagnosed with heartburn but actually is having a heart attack. The patient could die if he is sent home with antacids, instead of being given lifesaving treatments to open a blocked coronary artery. Conversely, if a patient has chest pain due to heartburn, but is misdiagnosed with a heart attack, he may suffer complications while undergoing unnecessary invasive cardiac procedures.

Diagnostic errors also may cause psychological harm. For example, a patient misdiagnosed with lung cancer when she actually has a benign lung problem could experience significant unnecessary anxiety about the serious side effects of proposed treatments, end-of-life care and her family’s well-being in the face of her illness.

Finally, diagnostic errors also can lead to financial harm because of the costs resulting from unnecessary treatments and related complications.

Proposed solutions

To tackle the complex problem of diagnostic errors in the U.S. health care system, the IOM report authors offered a wide range of useful recommendations, including:

  • Because the diagnostic process depends on successful collaboration among a team of many health care providers — including primary care physicians, specialists, nurses, and others — health care organizations need to facilitate and support teamwork in the diagnostic process among all team members. Better collaboration among pathologists, radiologists, other diagnostic specialists and treating health care providers would improve diagnostic testing processes.
  • Health care providers should include patients and their families as members of the diagnostic team, allowing them to be part of the diagnostic process. For example, patients could be given access to electronic health records, including clinical notes and diagnostic test results.
  • Medical schools and other professional health care educators should ensure that curricula and training programs address all aspects of performance in the diagnostic process.
  • Health information technology should be improved to better support the diagnostic process.
  • Accrediting organizations and Medicare should require that hospitals and other health care organizations establish programs to monitor the diagnostic process and identify, learn from and reduce diagnostic errors and near misses in a timely fashion.
  • The federal government should fund research on the diagnostic process and diagnostic errors.

Unfortunately, all too often such recommendations sit on the shelf gathering dust before they are implemented, if they ever are. Even if steps are taken to begin adopting these recommendations immediately, full implementation will require a substantial investment of time, money and effort. As a result, patients in the U.S. will continue to face the threat posed by diagnostic errors for many years to come.


[1] National Academies of Sciences, Engineering, and Medicine. Improving diagnosis in health care. Washington, DC: The National Academies Press; 2015. http://iom.nationalacademies.org/Reports/2015/Improving-Diagnosis-in-Healthcare.aspx. Accessed November 17, 2015.