Diagnostic usefulness of cerebrospinal fluid IgG in multiple sclerosis and other neurological disorders

MS is one of the most common neurologic disorders encountered in the United States. An increase in the CSF IgG index or IgG synthesis rate within CNS, and the presence of CSF oligoclonal bands, now serve as important tools for the diagnosis of MS. Although IEF shows better identification of a number of distinct oligoclonal bands compared to AGE, the latter appears to be a more convenient system for the average hospital's clinical laboratory. These findings are not specific to MS, and similar CSF abnormalities occur in other, more rarely neurologic diseases. It is generally easy to distinguish MS from these other diseases when a thorough clinical and laboratory evaluation is carried out. However, the detection of these CSF IgG abnormalities in non-MS patients may offer an important clue to the presence of a previously unsuspected chronic infection or inflammatory process involving the CNS.