Page Banner
Mayo Clinic Laboratories > Kappa Index Calculator

Kappa Index Calculator

The kappa free light chain (KFLC) index is interchangeable with oligoclonal bands (OCB) and consequently can replace oligoclonal bands for diagnosing multiple sclerosis (MS)1.The diagnostic sensitivity of the KFLC index (weighted average) was 88% (range 52%–100%) with a specificity of 89% (69%–100%), while OCB had a sensitivity of 85% (37%–100%) and a specificity of 92% (74%–100%)2.


Collection requirements: Spinal fluid (CSF) must be obtained within 7 days of serum collection.


Studies in MS evaluating the KFLC index did not find significant sensitivity differences across nephelometry or turbidimetry subgroups compared to OCB, thereby excluding the platform-type impact on the calculation2.

*Recommend that serum and CSF testing be performed on the same platform.

    Amount (mg/dL)

    Test Methodology

    CSF KFLC

    Please use the absolute value when a result is lower than the LLOQ. Ex: Kappa CSF result <0.0083, enter 0.0083


    Serum KFLC


    CSF Albumin

    Please use the absolute value when a result is lower than the LLOQ. Ex: CSF Albumin result <3.0, enter 3.0


    Serum Albumin


    Mayo Clinic Laboratories test options:

    CSF KFLC

    Serum KFLC

    CSF Albumin

    Serum Albumin


    Resources
    References
    1. Montalban X, Lebrun-Frénay C, Oh J, et al. Diagnosis of multiple sclerosis: 2024 revisions of the McDonald criteria. Lancet Neurol. 2025;24(10):850-865. doi:10.1016/S1474-4422(25)00270-4
    2. Hegen H, Walde J, Berek K, et al. Cerebrospinal fluid kappa free light chains for the diagnosis of multiple sclerosis: A systematic review and meta-analysis. Multiple Sclerosis Journal. 2023;29(2):169-181. Doi:10.1177/13524585221134213