The Oligoclonal Bands test is a test performed on the Cerebrospinal Fluid (CSF) of a person’s brain. Cerebrospinal fluid is the liquid layer which protects the brain and the spinal cord. Oligoclonal band is a type of immunoglobulin protein. The test is ordered in cases like neurological diseases and some central nervous inflammatory conditions. The test is also ordered when the doctor suspects MS disease. The CSF oligoclonal screen looks for these bands in your cerebrospinal fluid. Usually only one or two bands are present. The presence of multiple bands indicates that something is wrong. The test is also known as immunofixation.