This study was designed to evaluate fecal calprotectin levels in patients with fibromyalgia syndrome. Fecal calprotectin levels from fibromyalgia patients with and without gastrointestinal symptoms as well as healthy controls will be measured and compared.

Fecal calprotectin (FC) is a calcium and zinc binding protein that is present in neutrophil granulocytes and is detected in the stool samples from subjects with inflammatory bowel disease and similar organic gastrointestinal pathologies. Fibromyalgia is often accompanied by irritable bowel syndrome, which is a non-inflammatory, functional disorder of the gastrointestinal tract. Due to the chronic nature of the disease, fibromyalgia patients' new symptoms related to underlying gastrointestinal organic disease may be overlooked. In this study we aimed to assess the FC levels in fibromyalgia patients and healthy controls in order to detect a possible difference in FC levels between patients with and without gastrointestinal symptoms.

Inclusion Criteria:

• Groups 1 and 2: patients diagnosed as having Fibromyalgia syndrome according to American College of Rheumatology 2016 classification criteria (8). Group 3 will consist of healthy controls
• Older than 18 years of age

Exclusion Criteria:

• Presence of gastrointestinal symptoms starting after the age of 50.
• Presence of inflammatory rheumatological disorder
• Presence of organic gastrointestinal disorder
• History of fever, infective gastroenteritis, endoscopy or colonoscopy in the previous month
• Family history of inflammatory bowel disease
• Patients with alarm symptoms that required further investigation such as weight loss, nocturnal diarrhea, rectal bleeding
• Illiteracy

Adult subjects diagnosed as having FMS according to American College of Rheumatology 2016 classification criteria (1). Group 3 will consist of healthy controls