What is "oligoclonal band"

n. (context medicine English) One of bands of immunoglobulins that are seen when a patient's blood plasma or cerebrospinal fluid (CSF) is analyzed.

Oligoclonal bands (OCBs) are bands of immunoglobulins that are seen when a patient's blood serum, or cerebrospinal fluid (CSF) is analyzed.

Two methods of analysis are possible: (a) protein electrophoresis, a method of analyzing the composition of fluids, also known as "agarose gel electrophoresis/ Coomassie Blue staining", and (b) the combination of isoelectric focusing/silver staining. The latter is more sensitive.

For the analysis of cerebrospinal fluid, a patient has a lumbar puncture performed, which collects some of his or her cerebrospinal fluid. The blood serum can be gained from a clotted blood sample. Normally it is assumed that all the proteins that appear in the CSF but are not present in the serum are produced intrathecally (inside the CNS). Therefore it is normal to subtract bands in serum from bands in CSF when investigating CNS diseases.