The IgG Total Antibody ( CSf Fluid ) test measures the levels of immunoglobulin G (IgG) in cerebrospinal fluid (CSF), which helps evaluate immune response in the central nervous system. This test is used to diagnose conditions like multiple sclerosis, meningitis, and other neurological disorders involving inflammation or infection. Elevated IgG levels can indicate an immune response within the CSF, aiding in the assessment of disease progression or monitoring therapy effectiveness.