Dr. Andrea S. Tieng is a gastroenterologist in Rancho Cucamonga, California and is affiliated with multiple hospitals in the area, including San Antonio Regional Hospital and St. Bernardine Medical Center. She received her medical degree from State University of New York Downstate Medical Center College of Medicine and has been in practice for more than 20 years. Dr. Andrea S. Tieng has expertise in treating colonoscopy, upper gi endoscopy, among other conditions - see all areas of expertise. Dr. Andrea S. Tieng accepts Medicare, Aetna, Humana, Blue Cross, United Healthcare - see other insurance plans accepted.