There is no single test or symptom that can determine whether or not you have MS.1
Since many symptoms of MS are found in other conditions as well, confirming a diagnosis is often a process of eliminating other possibilities first.
If your doctor thinks MS may be causing your symptoms, he or she will refer you to a neurologist. Your neurologist will generally make a diagnosis based on detailed questions about your symptoms and your general health, as well as on the results of a number of tests. These might include:2
A neurological examination. This is a physical examination to check your movement, coordination, and balance; your mental, emotional, and language functioning; and your eyesight and other sensory abilities3
A magnetic resonance imaging (MRI) scan. This is a type of scan that uses magnetic fields to produce an image of your brain and spinal cord.4 Damage to the nerve covering (the myelin), with areas of scarring or inflammation, is seen in about 95% of people with definite MS5
Visual Evoked Potential (VEP) tests. These tests use small electrodes taped to your scalp to measure your reactions to different kinds of stimulation, such as flashing lights, moving patterns, and clicking noises. If there is a delay in your reaction time, there may be scarring along your nerve pathways, which may have been caused by MS1
A lumbar puncture. A lumbar puncture is performed to take a sample of the fluid that surrounds your brain and spinal cord to test for markers that support an MS diagnosis2
For someone living with MS, or for a person not yet diagnosed but who is experiencing symptoms, being diagnosed as early as possible is important. Studies show that early diagnosis and treatment at the first sign of MS can help keep the symptoms of MS at bay, slow down disability progression, and reduce the rate of relapses.4