Blood and Stool Molecular Biomarkers Longitudinal Detection Study in Crohn's Disease (CD) Patients

Inclusion Criteria: 1. Males and females with CD who are 18 years of age or older on the date of obtaining informed consent and are undergoing a colonoscopy at the study site. 2. The patient must have a confirmed diagnosis of CD based on results a complete medical evaluation and the assessment by a physician specialized in inflammatory bowel disease. 3. All CD patients should have no evidence for another active organic disease of the GI tract or medical problems as specified below in the exclusion criteria. 4. All patients must have a colonoscopic examination performed preferably on the same day as blood specimen is drawn, or blood may be drawn up to one week prior to colonoscopy. Stool specimen will be collected prior to the beginning of bowel prep for the colonoscopy, up to 10 days prior to bowel prep. 5. Understand the procedures and requirements of the study by providing written informed consent including consent and authorization for protected health information disclosure. Exclusion Criteria: 1. Extensive small bowel resection or short bowel syndrome. 2. Surgery for CD within the 6 months previous to enrollment. 3. Receipt of any blood products within 3 months prior to study entry. 4. Known pregnancy or breast feeding within 3 months of specimen collection. 5. Recent history of viral or bacterial gastroenteritis including Clostridium difficile infection \< 4 weeks prior to the blood draw 6. Concurrent diagnosis of another currently active erosive GI mucosal disease such as erosive esophagitis, gastric or duodenal ulcer, celiac sprue, diverticulitis, etc. 7. History of intestinal or colorectal cancer, of active autoimmune diseases, or of other chronic uncontrolled systemic disorders 8. History of bowel prep within the past 3 months. 9. History of alcohol or substance abuse. 10. History of prior colectomy or stricturing disease that could limit colonoscopy examination of small bowel mucosa. 11. Current ostomy or ileoanal pouch. 12. Current or previous (of less than 4 weeks prior) participation in in a clinical trial for an investigational drug.