Nephrology Associates PC

Dr. Daniel O_x2019_Brien is a gastroenterologist and is board certified by the American Board of Internal Medicine. He is dedicated to providing quality care in a friendly, caring and relaxed manner. He works on understanding the personalized needs of patients and building strong, long-lasting relationships. Dr. O_x2019_Brien provides care to adult patients with acute and chronic GI conditions. In addition to performing a variety of general GI procedures, he specializes in performing in-office hemorrhoid treatments. Dr. O_x2019_Brien is an avid sports fan. He enjoys spending quality time with his children and coaching youth sports.

At Optum, we help adults and children breathe easier and improve their overall health. With an office conveniently located in Brewster, NY, our allergists offer care for a wide range of issues including eczema, skin rashes, itchy eyes, hives, sinusitis and more. If you aren't sure what is causing your symptoms, our diagnostic testing can help poinpoint the problem. These tests include allergy skin/patch testing, asthma testing and environmental allergy testing. Optum accepts most major health plans.