Welcome to Vanguard Gastroenterology Clinic Located in New York, NY Vanguard Gastroenterology offer services that includes gastro consultations, clinical trials, colonoscopy procedure, upper endoscopy, screening colonoscopy, sigmoidoscopy exam, capsule endoscopy, ERCP, endoscopic ultrasound, integrative weight management, fecal microbiota transplantation and much more!SERVICES‧RESOURCES‧CONTACT‧OUR DOCTORS‧APPOINTMENTS‧BUSINESS HOURS.