Leurs, C. E.Twaalfhoven, H.Lissenberg-Witte, B. I.van Pesch, V.Dujmovic, IrenaDrulovic, J.Castellazzi, M.Bellini, T.Pugliatti, M.Kuhle, J.Villar, Luisa M.Álvarez Cermeño, José C.Alvarez Lafuente, R.Hegen, H.Deisenhammer, F.Walchhofer, L. M.Thouvenot, E.Comabella, ManuelMontalbán Gairín, XavierSaiz Hinarejos, AlbertPuma, D. LaVercammen, M.Vanopdenbosch, L.Uitdehaag, B. M. J.Killestein, J.Bridel, C.Teunissen, C.2021-01-112021-01-1120201352-4585https://hdl.handle.net/2445/173069Objective: To validate kappa free light chain (KFLC) and lambda free light chain (LFLC) indices as a diagnostic biomarker in multiple sclerosis (MS). Methods: We performed a multicenter study including 745 patients from 18 centers (219 controls and 526 clinically isolated syndrome (CIS)/MS patients) with a known oligoclonal IgG band (OCB) status. KFLC and LFLC were measured in paired cerebrospinal fluid (CSF) and serum samples. Gaussian mix- ture modeling was used to define a cut-off for KFLC and LFLC indexes. Results: The cut-off for the KFLC index was 6.6 (95% confidence interval (CI) = 5.2-138.1). The cut-off for the LFLC index was 6.9 (95% CI=4.5-22.2). For CIS/MS patients, sensitivity of the KFLC index (0.88; 95% CI = 0.85-0.90) was higher than OCB (0.82; 95%CI = 0.79-0.85; p < 0.001), but specificity (0.83; 95% CI = 0.78-0.88) was lower (OCB = 0.92; 95% CI = 0.89-0.96; p < 0.001). Both sensitivity and specificity for the LFLC index were lower than OCB. Conclusion: Compared with OCB, the KFLC index is more sensitive but less specific for diagnosing CIS/MS. Lacking an elevated KFLC index is more powerful for excluding MS compared with OCB but the latter is more important for ruling in a diagnosis of CIS/MS.12 p.application/pdfengcc by-nc (c) Leurs et al., 2020http://creativecommons.org/licenses/by-nc/3.0/es/Esclerosi múltipleMarcadors bioquímicsMultiple sclerosisBiochemical markersinfo:eu-repo/semantics/article6903002021-01-11info:eu-repo/semantics/openAccess31066634