Positive cerebrospinal fluid in the 2024 McDonald criteria for multiple sclerosis.
expert_opinion · Level V
Where this comes from
- Record sourced from PubMed, PMID 40967951.
- Also identified by DOI 10.1016/j.ebiom.2025.105905 and PMC identifier 12571584.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The 2024 McDonald diagnostic criteria for Multiple Sclerosis (MS) introduce kappa free light chains (κ-FLC) detection in cerebrospinal fluid (CSF) which can be used interchangeably with oligoclonal IgG bands (OCB) to demonstrate intrathecal immunoglobulin synthesis. Diagnostic sensitivity and specificity of κ-FLC is equal to OCB on a 95% confidence level. In rare cases determination of both, κ-FLC and OCB should be considered as the concordance rate is around 90%. We recommend calculating the κ-FLC index with values of ≥6.1 performing best for diagnosing MS. Validated turbidimetric or nephelometric assays should be applied for which proficiency testing programs are available. There is some prognostic use of the κ-FLC index with higher values predicting higher disease activity. Neurofilament light (NfL) should not be used for diagnostic purposes although it might be useful for prognosis and disease monitoring. All recommendations apply to paediatric and adult relapsing as well as progressive onset MS.
Medical subject headings
- Multiple Sclerosis