Faecal calprotectin is a faeces based test. Calprotectin is a chemical released into the faeces from white blood cells within the lining of the intestines. The white blood cells gather within the intestinal lining for many reasons including infection (such as food poisoning) and inflammatory bowel disease. The more white blood cells, the higher the calprotectin reading. If there are no or few white blood cells present, the faecal calprotectin should be within the normal range