36.4. Other applications of CSF FLC measurements

Chapter 36

CNS involvement is a rare complication of multiple myeloma with an extremely poor prognosis [1141]. Whilst magnetic resonance imaging (MRI) is usually the first diagnostic step in cases of suspected CNS involvement, CSF free light chain analysis can indirectly confirm the presence of the malignant plasma cell clone [1141].


  1. Why should a κ FLC index be used in preference to κ FLC concentrations to identify intrathecal immunoglobulin synthesis?


  1. Because correcting CSF κ FLC values using albumin measurements provides an indicator of whether the FLCs were produced locally, or have diffused from the blood due to blood/brain barrier dysfunction (Section 36.1).