New York City residents know that some medical conditions, owing to their rarity or a lack of specific symptoms, are frequently misdiagnosed. Three conditions in particular, known as the Big Three, are prone to diagnostic error: cancers, vascular events and infections. Yet medical experts are not exactly sure how many people are misdiagnosed.

Now, a study from Johns Hopkins University School of Medicine has taken five of the most misdiagnosed conditions in each of the three categories and calculated the rate of diagnostic errors. Nearly 10% of patients with one of the 15 conditions analyzed was misdiagnosed. These conditions included lung, breast and prostate cancer; heart attacks and stroke; and sepsis and pneumonia.

The rate of error ranged from 2.2% for heart attack patients to 62.1% for patients with spinal abscesses. Some of the percentages only seem low; for instance, 8.7% of stroke patients are misdiagnosed, but one must consider how common stroke is compared to spinal abscesses.

One in 20 patients who are misdiagnosed suffer serious harm. The 15 conditions analyzed account for nearly half of all cases involving serious misdiagnosis-related harm. Researchers said that there is no single reason why the Big Three are misdiagnosed. With the exception of heart attacks, though, doctors have not prioritized the immediate diagnosis of these conditions.

Many diagnostic errors are the result of negligence, or the failure of doctors to adhere to a standard of medical care. Before filing a medical malpractice claim, those hurt through a misdiagnosis or delayed diagnosis might want a lawyer to evaluate the case. It can be hard to negotiate for a settlement, so victims may hire the lawyer for assistance with this and every other step. If successful, a plaintiff may be compensated for past and future medical expenses, lost wages and more.