Persistent or recurrent abdominal pain and diarrhoea can be caused by the inflammatory bowel diseases, Crohn’s disease or ulcerative colitis, but can also be a feature of the irritable bowel syndrome. Diagnosis often needs colonoscopy which is both time consuming and unpleasant. The large bowel needs to be emptied and a flexible tube is passed under sedation to allow inspection of the lining of the large bowel and collection of samples for microscopic examination. On 15 July 2010 BMJ.com published a statistical analysis of research papers that had measured a protein called calprotectin in the stool of patients who had colonoscopy for suspected inflammatory bowel disease. The authors, from Groningen University in the Netherlands, concluded that a raised calprotectin levels in the stool identifies those who are most likely to need colonoscopy for diagnosis. A low faecal calprotectin safely excluded the condition in adults but was less good in children. Screening with calprotectin would reduce the number of adults needing colonoscopy by 67%.