Dr. Peifer is a board-certified gastroenterologist who joined Rockford Gastroenterology Associates in 2006 after completing his advanced endoscopy fellowship at Washington University School of Medicine in St. Louis. He received his medical degree from Medical College of Ohio and completed his internal medicine residency and gastroenterology fellowship at Washington University School of Medicine.

Dr. Peifer has served as the director of endoscopy at Rockford Gastroenterology Associates since 2012. He was the director of endoscopy at OSF HealthCare Saint Anthony Medical Center from 2012-2020 and served as president of the OSF Saint Anthony staff in 2019.

Dr. Peifer is a clinical assistant professor at the University of Illinois at Rockford and is involved in educating medical students and residents. He is a member of the American College of Gastroenterology (ACG), American Gastroenterology Association (AGA) and American Society for Gastrointestinal Endoscopy (ASGE).

Areas of expertise: Abnormal liver tests, biliary tract disorders, chronic liver disease including cirrhosis, fatty liver (NAFLD/NASH), gallstones and gallbladder disease, hepatitis B, hepatitis C, pancreatitis (acute and chronic), pancreatic cysts and masses.