Diagnosing medical conditions can be a tricky business at the best of times, but University of Virginia medical student Ryan Jones recently made the perfect call during a training exercise.

During the simulation last March, medical actor Jim Malloy's job was to accurately and convincingly portray a patient with the symptoms of abdominal aortic aneurysm, a condition in which a small section of the lower aorta begins to balloon.

The university medical facility says the condition is common in men between 65 and 75 years old, adding that such aneurysms can easily go undetected and possibly be fatal if they burst.

Even though it was just a simulation, Jones said he detected the symptoms of a real aneurysm. He felt a mass in Malloy's abdomen.

"I figured [the university] must have found a man with an aneurysm who was willing to volunteer," Jones said.

"I thought it was all prearranged," he said, adding that Malloy even kept in character when he informed him what he had found.

Jones informed an attending physician, who advised Malloy to consult a cardiologist.

A subsequent ultrasound revealed Malloy had a 5.9-centimetre-long aneurysm.

Last August, he underwent stent placement surgery at the university medical centre, and is now doing fine.

Since making that very real diagnosis, Jones has graduated from medical school and is currently applying for residency.

Click the audio at left to hear the interview from As It Happens with Jones and Malloy.