GI Study Guide 2026
Everything you need to pass the GI exam in one place: the exam format, every topic to study, real practice questions with explanations, flashcards, and full-length practice tests. Free, no sign-up needed.
📋 GI Exam Format at a Glance
📚 GI Topics to Study (21)
✍️ Sample GI Questions & Answers
1. What is the approximate transit time of contents through the entire colon in a healthy adult?
Normal colonic transit takes approximately 24 to 72 hours, though this can vary widely with diet and activity.
2. Azathioprine and 6-mercaptopurine are thiopurine immunosuppressants used in IBD; deficiency of which enzyme leads to toxic drug accumulation?
TPMT deficiency impairs thiopurine methylation, causing accumulation of cytotoxic thioguanine nucleotides and severe bone marrow suppression.
3. Fecal calprotectin is most useful for distinguishing which two conditions?
Fecal calprotectin is a sensitive noninvasive marker of intestinal inflammation, helping differentiate organic IBD from functional IBS.
4. Which modality is the preferred first-line imaging for suspected acute appendicitis in adult patients in the US?
CT abdomen/pelvis with IV contrast has the highest sensitivity (>95%) and specificity for diagnosing acute appendicitis in adults.
5. Roux-en-Y gastric bypass (RYGB) achieves weight loss primarily through which mechanism?
RYGB restricts stomach volume, reduces ghrelin (hunger hormone), and alters gut hormones (GLP-1, PYY) to improve satiety and insulin sensitivity, with modest malabsorption.
6. Which hormone, released by S cells in the duodenum, stimulates pancreatic bicarbonate secretion?
Secretin is released in response to acid entering the duodenum and stimulates pancreatic duct cells to secrete bicarbonate-rich fluid.