CSF Kappa Index is an indicator of intrathecal immunoglobulin synthesis and can substitute for CSF "oligoclonal bands" in supporting the diagnosis of Multiple Sclerosis using the 2024 revised McDonald criteria.
A Kappa Index result >/= 6.1 is consistent with intrathecal immunoglobulin synthesis
Ref: X Montalban et al. Diagnosis of multiple sclerosis: 2024 revisions of the McDonald criteria. Lancet Neurol 2025; 24: 850–65
NOTE: In samples where a Kappa Index cannot be calculated, an "oligoclonal bands" test may be reflexed. |