(CBS News) - A second opinion from a doctor could give you a second chance at survival, new research shows. The Mayo Clinic study found that as many as 88 percent of patients seeking a second opinion go home with a new or refined diagnosis. Twenty-one percent received a "distinctly different" diagnosis.
Conversely, the study, published in the Journal of Evaluation in Clinical Practice, found that only 12 percent of patients receive confirmation that the original diagnosis was complete and correct.
Second opinions that help patients get a more accurate and complete diagnosis could therefore lead to quicker access to appropriate medical care or prevent unnecessary treatments.
"Knowing that more than 1 out of every 5 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," lead researcher James Naessens, Sc.D., a health care policy researcher at Mayo Clinic, said in a statement.
In light of these findings, CBS News medical contributor Dr. David Agus called second opinions "critical."
"Obviously you want to get the right diagnosis so you can have the right treatment and there's no way to treat effectively unless you know what you're up against," he told "CBS This Morning" Tuesday.
So how do you know which opinion to believe? While this can be confusing for the patient, Agus has some advice.
"If there's a disorder that you have that is not getting better or is very serious, you want a second opinion," he said. "Obviously, going to a university medical center where doctors are classically more specialized, I would lean in the favor of that."
Sometimes, it may even be appropriate to get a third opinion. "If two doctors are vociferously arguing to do it one way or to do it another way, get a third opinion. The key is to get another set of eyes to look at what's going on," Agus said.
For the study, the researchers examined the records of 286 patients referred from primary care providers to Mayo Clinic's General Internal Medicine Division in Rochester from the beginning of 2009 to the end of 2010.
The researchers also calculated the average costs of getting a second opinion and found that it was thousands of dollars more when the diagnosis changed. However, experts note the cost is well worth it in the end.
"Paying up front is much more cost effective than down the road," Agus said. "Preventing a disease and intervening early has better outcomes."
Naessens notes that while "total diagnostic costs for cases resulting in a different final diagnosis were significantly higher than those for confirmed or refined diagnoses… the alternative could be deadly."
Finally, experts say patients shouldn't feel intimidated to ask for a second opinion or worry about offending their doctor.
"Most good doctors say, 'Listen, knowledge is better. I want my patient really comfortable with what I do,'" Agus said.