Duffin completed her Doctor of Medicine from the. Soon after this, she moved to Paris where she elected to study hematology and René Laennec at the Sorbonne. She completed her Doctor of Philosophy in the History of Medicine in 1985, she then returned to Canada.
She holds the Hannah Chair, History of Medicine at Queen"s University. Formerly, she was President of the American Association for the History of Medicine and Canadian Society for the History of Medicine. She is most well known for her testimony which led to the canonization of Marie-Marguerite d"Youville.
As of 2010, she has published eight books (as author and editor) on the history of medicine and has written numerous articles on various subjects relating to the history of medicine, miracles, and hematology.
Upon her return to Canada, Duffin settled in Ottawa where she took on a contract to review a set of slides, which she assumed were to be used in a malpractice suit. She was given no information about the patient, but identified the young woman as suffering from acute myeloblastic leukemia, “the most aggressive leukemia known.” As the slides were from some 5+ years earlier, she assumed the patient as deceased, as that form of leukemia kills usually within two years.
Instead, she found that the patient had, after a relapse, gone into remission and was doing well some five years on. Duffin"s testimony was to be used by the Vatican to determine whether Marie-Marguerite d"Youville (1701 – 1771) had performed a miracle and was worthy of canonization.
According to Duffin, “They never asked me to say this was a miracle.
They wanted to know if I had a scientific explanation for why this patient was still alive. I realized they weren’t asking me to endorse their beliefs. They didn’t care if I was a believer or not, they cared about the science.”.
