While there is no one specific medical test to diagnose MS, doctors can use a variety of tests to confirm MS, including: 

• MRIs;
• spinal taps;
• optical coherence tomography (non-invasive and painless imaging tool that views retinal structures behind the eye); and
• evoked potential tests (assess electrical activity in the brain). 

The NMSS explains that there are three criteria that must be present in order for doctors to confirm an MS diagnosis: 

• there must be at least two areas of the central nervous system that are affected;
• the damage must have occurred on two separate occasions; and
• all other diagnoses have been ruled out.