biostudies-literatureBjorklund JHUS Diagnostic centerSuomen kliinisen kemian yhdistysLaboratoriolääketieteen Edistämissäätiö sre70411https://www.ebi.ac.uk/biostudies/studies/S-EPMC12581111biostudies-literatureUnknown32(11)<h4>Background</h4>Kappa free light chain (KFLC)-based Kappa-index (K-index) can substitute oligoclonal banding (OCB) to detect intrathecal immunoglobulin synthesis. Cutoffs for positive results vary; therefore, further comparison of different approaches is necessary to optimize K-index for diagnostic utilization.<h4>Methods</h4>We analyzed 432 paired CSF/serum samples and selected 77 OCB-positive patients with multiple sclerosis (MS), clinically isolated syndrome (CIS) that did not progress to MS in > 10 years, and other neuroinflammatory diseases (non-MS). K-index subtests were measured on the Optilite platform (The Binding Site) and OCB with isoelectric focusing on the Hydrasys platform (Sebia).<h4>Results</h4>OCB positive cases had a higher K-index than OCB negative. The MS group had aEuropean journal of neurologyOptimized Kappa-Index Test Protocol to Detect Intrathecal Immunoglobulin Synthesis in Multiple Sclerosis.PMC12581111HUS/24/2024Bjorklund JOsterlund-Tauriala EAnttonen MSiuko MItkonen OTienari PJNokelainen PfalseOptimized Kappa-Index Test Protocol to Detect Intrathecal Immunoglobulin Synthesis in Multiple Sclerosis.<h4>Background</h4>Kappa free light chain (KFLC)-based Kappa-index (K-index) can substitute oligoclonal banding (OCB) to detect intrathecal immunoglobulin synthesis. Cutoffs for positive results vary; therefore, further comparison of different approaches is necessary to optimize K-index for diagnostic utilization.<h4>Methods</h4>We analyzed 432 paired CSF/serum samples and selected 77 OCB-positive patients with multiple sclerosis (MS), clinically isolated syndrome (CIS) that did not progress to MS in > 10 years, and other neuroinflammatory diseases (non-MS). K-index subtests were measured on the Optilite platform (The Binding Site) and OCB with isoelectric focusing on the Hydrasys platform (Sebia).<h4>Results</h4>OCB positive cases had a higher K-index than OCB negative. The MS group had a2025-01-01T00:00:00Z2025 Nov2026-06-05T11:32:24.762Z2026-05-16T03:12:22.458ZS-EPMC125811114118194510.1111/ene.70411