1035 Wellington Avenue , Grand Junction, CO 81501

To Schedule an Office Visit: 970.242.6600

About Us

Western Colorado’s Leading Gastroenterology Group

Grand Junction Gastroenterology is the largest gastroenterology group serving western Colorado. Our staff currently includes five board certified Gastroenterologists, two Physician Assistants and over 20 employees. Our goal is to provide our patients, referring physicians and the surrounding community with the best, most comprehensive, and highest quality of care possible.
 

Because gastrointestinal diseases require continuity of care, we strive to align patients with a single gastroenterologist who communicates with you, your primary care clinician, and your other specialists.
A gastroenterologist on staff is always on call for established patients with urgent needs.
Referred patients are evaluated in the clinic in person or by confidential telehealth. Although some testing is done in the clinic, the sedated endoscopies are performed by our physicians at the adjacent endoscopy center, St. Mary’s Hospital, Community Hospital, and Colorado Canyonlands Hospital.

We look forward to helping you.

Physicians


Physician Assistants

Our Office Policy

If you need to change or cancel your appointment, please contact us as soon as possible to reschedule. We request a minimum of 24-hour notice for a change concerning your appointment and reserve the right to charge a fee for missed appointments. Please note that appointments scheduled for Monday need to be cancelled by the previous Friday. Payment is due at the time of your appointment. If you have any questions regarding your insurance, please call your insurance company for the most accurate information. If you have any questions or concerns regarding financial arrangements, please call the billing number below.

Our Facility

Our facility is located at 1035 Wellington Avenue in Grand Junction, CO. and within the same building. Our goal is to create a friendly, comfortable environment with physicians specifically trained for your health care needs.

Our Physicians

Brent Prosser
Brent Prosser
MD
Dr. Prosser originally hails from Cheyenne, Wyoming. After receiving his degree in biology from Creighton University in Omaha, NE, he
William Shields
William Shields
DO, FACP, FACG
Dr Shields is a native of Colorado. He attended Western State Colorado University with a degree in biology followed by
George R. Winters III
George R. Winters III
MD, FACP, FACG
Dr. Winters graduated from Cornell University and the University of Vermont, College of Medicine. He completed his Internal Medicine residency
Philip Sarges
Philip Sarges
MD
Dr. Sarges has a passion for caring for people with gastrointestinal system disorders. He’s experienced in capsule endoscopy, fecal transplant,
Ellen Dy
Ellen Dy
MD
Dr. Dy graduated from Indiana University School of Medicine and completed her Internal Medicine Residency at the Indiana University Medical
Dan Castresana
Dan Castresana
MD
Dr. Dan Castresana, M.D., who is relocating with his wife and two daughters from Georgia, is a very skilled gastroenterologist
Michael Harris
Michael Harris
DO
Dr. Michael Harris, D.O. has just completed his training in all aspects of gastroenterology and hepatology care, including ERCP, at

Our Advanced Practice Providers

Hannah Pick
Hannah Pick
PA-C, MPAS
Hannah is a native of Grand Junction, Colorado. She is excited to be back in the Grand Valley with her
Katie Rabbio
Katie Rabbio
PA-C, MPAS
Katie is a Colorado native and is happy to be practicing in western Colorado. She has extensive experience working as
Leah Barjenbruch
Leah Barjenbruch
PA-C, MPAS
Leah has lived in Grand Junction for two years and has been practicing as a physician assistant for more than

Patient Testimonials

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What Sets Us Apart

Team Of Board-Certified Specialists

Providing Personalized & Innovative Gastroenterological Care

Utilizing The Latest & Most Advanced Techniques

Offering Long-Term Patient Follow-Up & Direct Physician Access