At this time, there are no symptoms, physical findings or laboratory tests that can — by themselves — determine if a person has MS. The doctor uses several strategies to determine if a person meets the MS diagnostic criteria. In order to make a diagnosis of MS, the physician must:

• Find evidence of damage in at least two separate areas of the central nervous system (CNS), which includes the brain, spinal cord and optic nerves AND
• Find evidence that the damage occurred at two different points in time AND
• Rule out all other possible diagnoses.

In 2001, the International Panel on the Diagnosis of Multiple Sclerosis updated the criteria to include specific guidelines for using magnetic resonance imaging (MRI), cerebrospinal fluid (CSF) analysis, and visual evoked potentials (EP) to speed the diagnostic process. These tests can be used to look for a second area of damage in a person who has experienced only one relapse (also called an attack or exacerbation) of MS-like symptoms — referred to as a clinically-isolated syndrome (CIS). A person with CIS may or may not go on to develop MS. The criteria (now referred to as The Revised McDonald Criteria) were further revised in 2005 and again in 2010 to make the process even easier and more efficient.