{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,16]],"date-time":"2026-09-16T17:03:09Z","timestamp":1789578189135,"version":"build-2803163510"},"reference-count":0,"publisher":"SAGE Publications","license":[{"start":{"date-parts":[[2026,9,15]],"date-time":"2026-09-15T00:00:00Z","timestamp":1789430400000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.sagepub.com\/page\/policies\/text-and-data-mining-license"}],"funder":[{"name":"ARC NWC NIHR","award":["ARCNWC 622"],"award-info":[{"award-number":["ARCNWC 622"]}]}],"content-domain":{"domain":["journals.sagepub.com"],"crossmark-restriction":true},"short-container-title":["Ann Clin Biochem"],"abstract":"<jats:p>Background \r\nMeasurement of kappa free light chains (\u03baFLC) in cerebrospinal fluid (CSF) has been demonstrated as a quantitative biomarker for neuroinflammation. CSF \u03baFLC may be displayed in several forms, often using a peripheral \u03baFLC measurement as a denominator to highlight intrathecal rather than systemic inflammation. This study seeks to contextualise CSF \u03baFLC as an alternative to oligoclonal band (OCB) analysis.\r\nMethods \r\nPatient samples were separated into 2 distinct cohorts by clinical diagnosis and OCB result. \u03baFLC, IgG, albumin and OCB were analysed for paired CSF and serum samples (n=104); CSF cell counts were also performed. Quotient calculations for \u03baFLC were performed and hyperbolic reference curves drawn.\r\nResults \r\nComparison of \u03baFLC and OCB results showed that samples with 2 or more unmatched OCB gave significantly different CSF \u03baFLC determinations in all \u03baFLC result formats (p &lt;0.001) compared with other OCB cohorts. CSF \u03baFLC also correlated with \u22651 unmatched OCB. All multiple sclerosis (MS) patients gave significantly different \u03baFLC determinations in all \u03baFLC result formats (p &lt;0.001) between MS and non-MS cohorts. Using a \u03baFLC index cut-off \u226516 gave PPV and NPV of 85% and 94% for MS.\r\nConclusions\r\nCSF \u03baFLC has been incorporated into the 2024 revision of the McDonald Criteria. This study supports CSF \u03baFLC as a quantitative, non-specific biomarker for MS. Advantages of \u03baFLC in a laboratory repertoire include simple analysis available on common analytical platforms. We recommend that CSF \u03baFLC should be used in conjunction with OCB for samples without a clear positive or negative result.<\/jats:p>","DOI":"10.1177\/00045632261492540","type":"journal-article","created":{"date-parts":[[2026,9,15]],"date-time":"2026-09-15T13:43:10Z","timestamp":1789479790000},"update-policy":"https:\/\/doi.org\/10.1177\/sage-journals-update-policy","source":"Crossref","is-referenced-by-count":0,"title":["CSF Kappa Free Light Chain: An enhancement to Oligoclonal Bands? A Tertiary Centre Cohort."],"prefix":"10.1177","author":[{"ORCID":"https:\/\/orcid.org\/0009-0005-4691-8444","authenticated-orcid":false,"given":"Nicholas Alexei Eric","family":"Armfield","sequence":"first","affiliation":[{"name":"The Walton Centre NHS Foundation Trust"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sally","family":"Hanton","sequence":"additional","affiliation":[{"name":"The Walton Centre NHS Foundation Trust"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nicola","family":"Williams","sequence":"additional","affiliation":[{"name":"The Walton Centre NHS Foundation Trust"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0008-4984-7962","authenticated-orcid":false,"given":"Katherine","family":"Birch","sequence":"additional","affiliation":[{"name":"The Walton Centre NHS Foundation Trust"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Robert","family":"Tate","sequence":"additional","affiliation":[{"name":"The Walton Centre NHS Foundation Trust"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Edward","family":"Jackson","sequence":"additional","affiliation":[{"name":"The Walton Centre NHS Foundation Trust"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9881-9203","authenticated-orcid":false,"given":"Carrie","family":"Chadwick","sequence":"additional","affiliation":[{"name":"The Walton Centre NHS Foundation Trust"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"179","published-online":{"date-parts":[[2026,9,15]]},"container-title":["Annals of Clinical Biochemistry: International Journal of Laboratory Medicine"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/journals.sagepub.com\/doi\/pdf\/10.1177\/00045632261492540","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/journals.sagepub.com\/doi\/pdf\/10.1177\/00045632261492540","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,9,16]],"date-time":"2026-09-16T16:17:41Z","timestamp":1789575461000},"score":1,"resource":{"primary":{"URL":"https:\/\/journals.sagepub.com\/doi\/10.1177\/00045632261492540"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,9,15]]},"references-count":0,"alternative-id":["10.1177\/00045632261492540"],"URL":"https:\/\/doi.org\/10.1177\/00045632261492540","relation":{},"ISSN":["0004-5632","1758-1001"],"issn-type":[{"value":"0004-5632","type":"print"},{"value":"1758-1001","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,9,15]]},"article-number":"00045632261492540"}}