RT Journal Article SR Electronic T1 Diagnostic significance of IgG and albumin indices versus oligoclonal band types in demyelinating disorders JF Journal of Clinical Pathology JO J Clin Pathol FD BMJ Publishing Group Ltd and Association of Clinical Pathologists SP 166 OP 171 DO 10.1136/jclinpath-2021-207766 VO 76 IS 3 A1 Belimezi, Maria A1 Kalliaropoulos, Antonios A1 Mentis, Alexios-Fotios A A1 Chrousos, George P YR 2023 UL http://jcp.bmj.com/content/76/3/166.abstract AB Aims The laboratory diagnosis of demyelinating inflammatory disorders (DIDs) relies on both intrathecal oligoclonal band (OCB) positivity and IgG index. Although OCB typing remains the gold-standard test for DIDs, it can be laborious and ambiguous, complicating diagnostics, and unduly increasing diagnostic time. We examined whether serum or cerebrospinal fluid (CSF) parameters can classify OCB types and, thus, be used as a replacement test to standard OCB typing.Methods We retrospectively analysed >1000 prospectively collected samples of patients with DIDs and quantified albumin and IgG levels in the CSF and serum. We determined OCB types by isoelectric focusing combined with immunofixation and evaluated the diagnostic accuracies of IgG and albumin indices in discriminating OCB types by receiver operating characteristic curves and multinomial regression.Results An IgG index cut-off of 0.589 differentiated types 2/3 from types 1/4 (area under the curve 0.780, 95% CI 0.761 to 0.812, p<0.001; specificity: 71.10%, sensitivity: 73.45%). Albumin quotient cut-off values of 6.625 and of 6.707 discriminated type 1 from type 4 and type 2 from type 3, respectively (specificity: <55%, sensitivity: <75%). Female sex, age, IgG index, CSF IgG and serum albumin were associated with different OCB types.Conclusions Our study reveals that IgG and albumin index can differentiate OCB types with adequate accuracy, especially if refined by age and gender.Data are available upon reasonable request. Data Availability The data are available upon reasonable request.