Mucositis is. A clinical diagnosis. There really is not a specific test for mucositis that would generally be utilized and instrumenting a patient to directly visualize mucosal breakdown in the setting of cancer therapy would be discouraged due to bleeding and infection risks. We make this diagnosis based upon symptoms (pain, drooling, loose stool, etc) and signs (erythema/erosion of mucosal surfaces, etc).
Thorough exam. Mucositis can be caused from a number of different things. A thorough history and clinical examination is the first step. In some cases, additional diagnostic tests may be indicated that may include blood work, cytology, and/or biopsies of the affected area (s).