Differentiating Between Lactose Intolerance, Celiac Disease, and Irritable Bowel Syndrome-Diarrhea

The purpose of this article is to assist nurse practitioners (NPs) and other primary care providers in differentiating between lactose intolerance, celiac disease, and diarrhea-predominant irritable bowel syndrome in adults. Based on subtle characteristics gathered from the history and physical examination, the NP's examination and approach to testing will help distinguish between the 3 conditions. NPs should use a sequential process of examination and testing to distinguish gastrointestinal disorders that share common symptoms. A best practice algorithm is provided.