: Oligoclonal Bands, Serum and Plasma, Isoelectric Focusing

: What Are Oligoclonal Bands?

: Oligoclonal bands are small groups of antibodies (immunoglobulins) that appear as distinct bands when proteins in a sample are separated by a laboratory technique called electrophoresis. In a healthy person, antibodies are usually diverse and spread out; oligoclonal bands indicate that a limited number of antibody-producing cell types are active.

: Why Blood (Serum or Plasma) Is Tested

: Oligoclonal bands are most meaningful when measured in cerebrospinal fluid, the fluid surrounding the brain and spinal cord. Testing serum or plasma at the same time lets the laboratory compare the two samples to determine whether any bands are being produced within the central nervous system or are simply circulating in the blood.

: How the Sample Is Collected

: A serum or plasma sample is obtained from a routine blood draw, usually from a vein in your arm. The laboratory separates the proteins and examines the banding pattern. Your provider typically orders this test together with a CSF sample collected by lumbar puncture.

: What the Results Mean

: The laboratory reports whether oligoclonal bands are present and whether the pattern in CSF differs from that in serum or plasma. Results are interpreted together with your symptoms, imaging, and other tests; they do not by themselves confirm or rule out a specific diagnosis.