Dr. Tierney is board certified in internal medicine with specialties in gastroenterology and colon cancer for patients aged 18 and up. Dr. Tierney received his medical degree from the University of Illinois Medical School, Chicago, Illinois in 1988. He then completed an internship in internal medicine at Jewish Hospital, Washington University in St. Louis, where he also served his residency. After that, he completed a fellowship in gastroenterology at Loyola University in Chicago, Illinois. Dr. Tierney is a member of the Board of Directors of the American Cancer Society, High Plains Division.