Cerebrospinal fluid; Oligoclonal free light chains; Oligoclonal IgG

Aims. To compare the sensitivity and specificity of CSF-restricted oligoclonal IgG and free light chains as markers of multiple sclerosis and other inflammatory neurological diseases. Methods. 196 paired CSF and serum samples were examined for oligoclonal IgG and oligoclonal free light chains. The sensitivity and specificity of the tests were calculated and optimal cut-offs for the number of CSF-restricted oligoclonal bands were then determined by analysis of receiver operating characteristic curves. Results. Optimal cut-off values were ?5 IgG bands for multiple sclerosis, ?4 IgG bands for inflammatory neurological disease, ?6 free ?, and ?2 free ? bands for both purposes. Using these cut-off values, sensitivities and specificities for multiple sclerosis were 83.8% and 91.3% for IgG, 83.8% and 81.0% for free ?, and 67.6% and 75.4% for free ?. For inflammatory neurological disease, sensitivities and specificities were 60.8% and 95.7% for IgG, 69.6% and 92.6% for free ?, and 64.8% and 86.2% for free ?.