Table 1.

Various κ-FLC parameters investigated in MS.

■ CSF κ-FLC concentration ■  $Q_{\mathrm{k}-\mathrm{FLC}}=\frac{\kappa -{\mathrm{FLC}}_{CSF}}{\kappa -{\mathrm{FLC}}_{Serum}}$ ■  $\kappa -\mathrm{FLC}\mathrm{index}=\frac{\frac{\kappa -{\mathrm{FLC}}_{CSF}}{\kappa -{\mathrm{FLC}}_{Serum}}}{\frac{{\mathrm{Albumin}}_{CSF}}{{\mathrm{Albumin}}_{Serum}}}$ ■ IF κ-FLC with different underlying formulae to determine the Qalb-dependent upper reference limit (Qlim κ-FLC) and, thus, the limit to define IFκ-FLC - Presslauer et al.: 20 $Q_{\lim -FLC}=0.9358\times Q_{alb}^{0.6687}$ - Hegen et al.: 21 $Q_{\lim -FLC}=3.1276\times Q_{alb}^{0.8001}$ - Senel et al.: 22 $Q_{\lim -FLC}=9.5+2.08\times Q_{alb}$ - Reiber et al.: 23 $Q_{\lim -FLC}=3.27\times {(Q_{alb}^2+33)}^{0.5}-8.2\times {10}^{-3}$

CSF: cerebrospinal fluid; FLC: free light chain; IF: intrathecal fraction; Q_alb: CSF/serum albumin quotient.