A study conducted by James Naessens, ScD, a healthcare policy researcher at Mayo Clinic, published in the Journal of Evaluation in Clinical Practice, showed how a second opinion can affect the final diagnoses of a patient’s condition.

When patients have an ambiguous or undiagnosed condition, it is common to refer to another physician for a second opinion. The additional insight can impact the final diagnosis, which was the focus of the the Mayo Clinic study.

“Effective and efficient treatment depends on the right diagnosis,” said Naessens. “Knowing that more than one out of every five referral patients may be completely [and] incorrectly diagnosed is troubling─not only because of the safety risks for these patients prior to correct diagnosis, but also because of the patients we assume are not being referred at all.”

Examining the difference in diagnostic outcomes, the study included 286 patients referred from their clinicians to Mayo Clinic’s General Internal Medicine Division from 2009 through 2010. Patients initial and final diagnoses were compared to measure diagnostic differences.

Results showed that only 12 percent of initial diagnoses were the same as the final ones. Two thirds (66 percent) of final diagnoses were improved. Also, in 21 percent of patients, the final conclusion differed significantly from the initial diagnoses. By showcasing the importance of a second opinion and additional insights on diagnoses, researchers hope to incorporate these finding in healthcare systems in order to reduce medical error.

“This may prevent identification of diagnostic error and could lead treatment delays, complications leading to more costly treatments or even patient harm or death,” said Naessens. “We want to encourage second opinions when the provider is not certain.”