Doctors are often required to diagnose complaints of abdominal pain and mild diarrhea that are mostly due to functional causes such as irritable bowel syndrome, lactose intolerance, and transient effects of gastrointestinal infections. The decision of whether to refer these patients for invasive tests like colonoscopy and gastroscopy to rule out inflammatory bowel diseases (Crohn's and ulcerative colitis) depends on the level of clinical suspicion. These diseases can sometimes manifest with atypical symptoms, which might delay the time from the onset of symptoms to diagnosis and treatment. Studies have shown that the time to diagnose Crohn's disease can be as long as a year or even more.
Inflammatory markers in the blood can be checked (mainly CRP - C-Reactive Protein) along with erythrocyte sedimentation rate (ESR) as indirect indicators, but these aren't entirely accurate. About a quarter of patients with mild inflammation in inflammatory bowel diseases receive completely normal blood test results (especially true for ulcerative colitis). The need to accurately assess the level of inflammation in the intestines exists even during diagnosed and known disease. The symptoms do not always reflect the state of intestinal inflammation, especially in Crohn's disease. Recent studies indicate a clear connection between achieving mucosal healing of the intestine and a better prognosis of disease inactivity and remission. Therefore, we want to know not only about the patient's complaints but also about the state of the intestine itself. For this purpose, the treating physician has specialized tests for inflammatory bowel diseases, such as Calprotectin in stool and blood serology. In addition, innovative tests are available to tailor drug treatment specifically for each patient.