The diagnosis of multiple sclerosis is based on a history of symptoms, findings on from a neurological exam, and a combination of laboratory and radiology tests. Because there is not a definitive test to confirm MS and symptoms can be the same as those of other nervous system disorders, diagnostic tests will help rule out other causes in addition to confirming a diagnosis.

These tests may include a magnetic resonance imaging (MRI) scan of the brain and spinal cord. More than 90 percent of people who have MS have an abnormal MRI. For people already diagnosed with multiple sclerosis, MRI scans also may be used to follow the progression of the disease.

The patient's medical team may order a lumbar puncture, also known as a spinal tap, and cerebrospinal fluid analysis, as well as nerve function tests.

Blood tests may be performed to rule out other conditions that have similar symptoms.

A diagnosis of multiple sclerosis is confirmed when the following are present without another explanation for the symptoms:

  • The patient has had at least two neurologic episodes with signs and symptoms of MS (weakness or clumsiness, vision problems, tingling or numbness, or balance problems) lasting at least 24 hours and occurring at least one month apart.
  • There is at least one symptom that indicates an injury to one part of the central nervous system, and laboratory tests show abnormal findings in at least one other area of the central nervous system.