Diagnostic Value of κ-FLC in OCB-Negative Patients

In a study of 141 human patients, 83% had measurable cerebrospinal fluid (CSF) κ-FLC, and 43% had a positive κ-FLC index. The findings suggested that an MS diagnosis could have been made 4.9 months earlier for patients who met the dissemination in space (DIS) criteria but not dissemination in time (DIT) criteria.

Tags: #Biomarkers
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Source: Read original source (PMID 42756799)

This plain-English summary was written by AI from a published abstract and may contain errors. It is not medical advice. Read the original study and talk to your MS team before making decisions about treatment.

Why it matters

This study highlights that the κ-FLC index may help in diagnosing MS earlier in patients without typical oligoclonal bands, potentially improving patient management.

What this does not prove

The study is retrospective and focused on a specific cohort, which may limit how widely the results can be applied.

Next milestone

No next milestone was established from the available source.

Study facts

Study design: Not reported
Participants / samples: 141 · basis not reported
Randomised: Not reported
Controlled: Not reported
Primary endpoint met: Not reported
Relevant MS type: All
Publication date: 2026-09-03
Evidence reviewed: Abstract only
Regulatory approval: Not reported
Research areas: Biomarkers

Original sources

Primary evidenceDiagnostic value of the kappa free light chain index in multiple sclerosis under the 2024 CSF positivity criterion: a multicentre study in oligoclonal band-negative patients. ↗DOI: 10.3389/fimmu.2026.1848491

Supporting passages (8)

subjectsincluded in this multicentre retrospective study.

sample sizeAmong 141 enrolled patients

research categoriesThis study aimed to evaluate the contribution of the κ-FLC index to the diagnosis of MS, through the CSF positivity criterion, in OCB-negative patients.

relevant ms typesA MS diagnosis was met at the time of the lumbar puncture in 102 patients, through the fulfilment of both the 2017 dissemination in space (DIS) and time (DIT) criteria.

publication date2026-09-03

primary endpointthe κ-FLC index may contribute to an earlier MS diagnosis in OCB-negative patients fulfilling the DIS but not the DIT criteria.

findingsConsidering the contribution of the κ-FLC index to the CSF positivity criterion, a MS diagnosis could have been anticipated in these patients by a median of 4.9 months (IQR: 1.8-14.1).

limitationsTitle: Diagnostic value of the kappa free light chain index in multiple sclerosis under the 2024 CSF positivity criterion: a multicentre study in oligoclonal band-negative patients.

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