{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,25]],"date-time":"2026-09-25T18:17:43Z","timestamp":1790360263676,"version":"4.1.0"},"reference-count":33,"publisher":"Wiley","issue":"9","license":[{"start":{"date-parts":[[2025,9,6]],"date-time":"2025-09-06T00:00:00Z","timestamp":1757116800000},"content-version":"vor","delay-in-days":5,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/"}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Euro J of Neurology"],"published-print":{"date-parts":[[2025,9]]},"abstract":"ABSTRACT<\/jats:title>\n \n Background<\/jats:title>\n \n No standardized strategy for integrating\n \u03ba<\/jats:italic>\n \u2010free light chain (\n \u03ba<\/jats:italic>\n \u2010FLC) index into routine cerebrospinal fluid (CSF) diagnostics has yet been established.\n <\/jats:p>\n <\/jats:sec>\n \n Objective<\/jats:title>\n \n To determine agreement between\n \u03ba<\/jats:italic>\n \u2010FLC index and CSF\u2010restricted oligoclonal bands (OCB), and to identify\n \u03ba<\/jats:italic>\n \u2010FLC index range where second\u2010line OCB testing is needed.\n <\/jats:p>\n <\/jats:sec>\n \n Methods<\/jats:title>\n \n A retrospective analysis was conducted in patients who had\n \u03ba<\/jats:italic>\n \u2010FLC measurement between December 2023 and December 2024 at the Medical University of Innsbruck.\n \u03ba<\/jats:italic>\n \u2010FLC in CSF and serum was determined by nephelometry; OCB by isoelectric focusing and immunoblotting. The threshold for positivity was defined as \u2265\u20093 CSF\u2010restricted bands for OCB and \u2265\u20096.1 for\n \u03ba<\/jats:italic>\n \u2010FLC index.\n <\/jats:p>\n <\/jats:sec>\n \n Results<\/jats:title>\n \n In 632 included samples,\n \u03ba<\/jats:italic>\n \u2010FLC index ranged from 0.5 to 971. Among 213 samples with\n \u03ba<\/jats:italic>\n \u2010FLC index \u2265\u20093.5, 180 (85%) samples had a positive\n \u03ba<\/jats:italic>\n \u2010FLC index and 148 (69%) positive OCB. Thirty\u2010four (16%) samples showed discordant results. One sample was OCB positive\/\n \u03ba<\/jats:italic>\n \u2010FLC index negative, showing markedly elevated serum\n \u03ba<\/jats:italic>\n \u2010FLC values. Thirty\u2010three samples were OCB negative\/\n \u03ba<\/jats:italic>\n \u2010FLC index positive; of those, 4 samples had isolated intrathecal immunoglobulin M or A synthesis, and the remaining 29 discordant samples showed a median\n \u03ba<\/jats:italic>\n \u2010FLC index of 8.7 (75th percentile: 10.3). The predictive value for OCB positivity exceeded 95% in the case of\n \u03ba<\/jats:italic>\n \u2010FLC index >\u200920.\n <\/jats:p>\n <\/jats:sec>\n \n Conclusion<\/jats:title>\n \n \u03ba<\/jats:italic>\n \u2010FLC index shows high agreement with OCB. Discordant results were largely confined to\n \u03ba<\/jats:italic>\n \u2010FLC index between 3.5 and 20 (\u201cgray zone\u201d). A reflex approach, that is, initial screening with\n \u03ba<\/jats:italic>\n \u2010FLC index and in case of values within the \u201cgray zone\u201d performing OCB, seems reasonable.\n <\/jats:p>\n <\/jats:sec>","DOI":"10.1111\/ene.70355","type":"journal-article","created":{"date-parts":[[2025,9,6]],"date-time":"2025-09-06T07:04:29Z","timestamp":1757142269000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":12,"title":["Kappa Free Light Chain Index in the Real World\u2014Do We Miss Clinically Relevant Information by Skipping Oligoclonal Banding?"],"prefix":"10.1111","volume":"32","author":[{"given":"Harald","family":"Hegen","sequence":"first","affiliation":[{"name":"Department of Neurology Medical University of Innsbruck Innsbruck Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0007-3081-854X","authenticated-orcid":false,"given":"Martin","family":"Schmidauer","sequence":"additional","affiliation":[{"name":"Department of Neurology Medical University of Innsbruck Innsbruck Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Michael","family":"Auer","sequence":"additional","affiliation":[{"name":"Department of Neurology Medical University of Innsbruck Innsbruck Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Franziska","family":"Di Pauli","sequence":"additional","affiliation":[{"name":"Department of Neurology Medical University of Innsbruck Innsbruck Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Klaus","family":"Berek","sequence":"additional","affiliation":[{"name":"Department of Neurology Medical University of Innsbruck Innsbruck Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Janette","family":"Walde","sequence":"additional","affiliation":[{"name":"Department of Statistics, Faculty of Economics and Statistics University of Innsbruck Innsbruck Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Florian","family":"Deisenhammer","sequence":"additional","affiliation":[{"name":"Department of Neurology Medical University of Innsbruck Innsbruck Austria"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2025,9,6]]},"reference":[{"key":"e_1_2_8_2_1","doi-asserted-by":"publisher","DOI":"10.1177\/13524585221134217"},{"key":"e_1_2_8_3_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.lanepe.2024.101009"},{"key":"e_1_2_8_4_1","doi-asserted-by":"publisher","DOI":"10.1007\/s10354-022-00912-7"},{"key":"e_1_2_8_5_1","doi-asserted-by":"publisher","DOI":"10.1177\/13524585221134213"},{"key":"e_1_2_8_6_1","doi-asserted-by":"publisher","DOI":"10.1212\/NXI.0000000000200049"},{"key":"e_1_2_8_7_1","doi-asserted-by":"publisher","DOI":"10.1212\/NXI.0000000000001005"},{"key":"e_1_2_8_8_1","doi-asserted-by":"publisher","DOI":"10.1111\/jnc.15500"},{"key":"e_1_2_8_9_1","doi-asserted-by":"publisher","DOI":"10.1111\/ene.13667"},{"key":"e_1_2_8_10_1","doi-asserted-by":"publisher","DOI":"10.3389\/fimmu.2023.1288169"},{"key":"e_1_2_8_11_1","doi-asserted-by":"publisher","DOI":"10.1093\/labmed\/lmae101"},{"key":"e_1_2_8_12_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.mayocp.2021.09.014"},{"key":"e_1_2_8_13_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.msard.2023.104997"},{"key":"e_1_2_8_14_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.autrev.2025.103765"},{"key":"e_1_2_8_15_1","doi-asserted-by":"publisher","DOI":"10.1212\/WNL.0b013e3181c47cc2"},{"key":"e_1_2_8_16_1","doi-asserted-by":"publisher","DOI":"10.3389\/fimmu.2021.675307"},{"issue":"3","key":"e_1_2_8_17_1","first-page":"489","article-title":"Clinical Comparison of New Monoclonal Antibody\u2010Based Nephelometric Assays for Free Light Chain Kappa and Lambda to Polyclonal Antibody\u2010Based Assays and Immunofixation Electrophoresis","volume":"50","author":"Hoedemakers R. 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