Multiple sclerosis Multiple sclerosis (MS) is a disease that affects the spinal cord and brain. There is not just one test to diagnose it, there are multiple tests. It is usually diagnosed based on symptoms and signs, including laboratory tests. Multiple sclerosis can be difficult to diagnose because all of the symptoms can be comparable to other medical problems. According to the Diagnostic and Statistical Manual of Mental Disorders, the diagnostic process of multiple sclerosis has three elements to reach a diagnosis. The first is the patient's history. The second is the neurological examination (testing of the nervous system and its function). The third is a variation of specialized procedures. These may include inspections of the cerebrospinal fluid (fluid that flows through the spine), different types of X-rays, and numerous electrical tests. Another important feature of multiple sclerosis is that symptoms come and go in about two-thirds of MS patients. When these symptoms are present it is called a flare-up, when they are not it is called a flare-up...