Vineet Chopra, University of Michigan and Sanjay Saint, University of Michigan

When a person goes to the doctor, there’s usually one thing they want: a diagnosis. Once a diagnosis is made, a path toward wellness can begin.

In some cases, diagnoses are fairly obvious. But in others, they aren’t.

Consider the following: A 50-year-old man with a history of high blood pressure goes to the emergency room with sudden chest pain and difficulty breathing.

Concerned that these are symptoms of a heart attack, the ER physician orders an electrocardiogram and blood tests. The tests are negative, but sometimes heart attacks don’t show up on these tests. Since every minute counts, he prescribes a blood thinner to save the patient’s life.

Unfortunately, the diagnosis and decision was wrong. The patient was not having a heart attack. He had a tear in his aorta (known as an aortic dissection) – a less obvious but equally dangerous condition.

It’s not a far-fetched scenario.

“Three’s Company” star John Ritter died from an aortic tear that doctors initially diagnosed and treated as a heart attack.

With over three decades of combined experience caring for patients in hospital settings, we have faced our share of diagnostic dilemmas. Determined to improve our practice and those of other physicians, we are studying ways to prevent diagnostic errors as part of a project funded by the federal government’s Agency for Healthcare Research and Quality. Below, we describe some of the challenges – and possible solutions – to improving diagnosis.

The flawed thought processes that result in errors

When physicians learn to make diagnoses in medical school, they are trained to initiate a mental calculus, analyzing symptoms and considering the possible conditions and illnesses that may cause them. For instance, chest pain could indicate a problem with the cardiovascular or respiratory system. Keeping in mind these systems, students then ask what conditions may cause these problems, focusing first on the most life-threatening ones such as heart attack, pulmonary embolism, collapsed lung or aortic tears.

Once tests rule these out, less dangerous diagnoses such as heartburn or muscle injury are considered. This process of sifting through possibilities to explain a patient’s symptoms is called generating a “differential diagnosis.”

Although the ER physician in our example could have stopped to generate a differential diagnosis, this is easier said than done. With time and experience, mental shortcuts overshadow this time-consuming process and mistakes may result.