Tehran University of Medical Sciences Iranian Journal of Parasitology 1735-7020 13 3 2018 09 24 505 509 EN Sara MOHAMMAD ALI GOL Behbood Research Center for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran Hamed MIRJALALI Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran Hamid ASADZADEH AGHDAEI Basic and Molecular Epidemiology of Gastrointestinal Disorders Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran Mohammad Reza ZALI Gastroenterology and Liver Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran 2017 03 04 2017 07 12 Inflammatory bowel disease (IBD) is attributed to complex conditions of gastrointestinal tract that is frequently reported all over the world. Fecal calprotectin evaluation is described as a primary tool to screen IBD patients. There are reports showing the confounding role of some microbial agents in diagnostic levels of calprotectin. A 32-yr-old woman with symptoms like IBD/IBS (irritable bowel syndrome); admitted to IBD Clinic of Behbood Research Center for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran, Jan 2017 for evaluation of the level of fecal calprotectin. In spite of high level of calprotectin, trophozoite of Giardia intestinalis was observed in direct examination of stool sample. Microbial pathogens can lead to false elevation of fecal calprotectin and misdiagnosis of gastrointestinal patients suspected to IBD. https://ijpa.tums.ac.ir/index.php/ijpa/article/view/1539 https://ijpa.tums.ac.ir/index.php/ijpa/article/download/1539/866