Determination of κFLC and κ Index in cerebrospinal fluid: a valid alternative to assess intrathecal immunoglobulin synthesis

J Neuroimmunol. 2013 Oct 15;263(1-2):116-20. doi: 10.1016/j.jneuroim.2013.07.006. Epub 2013 Aug 1.


Intrathecal immunoglobulin synthesis is observed in several disorders of the central nervous system, but its detection by current laboratory tests is relatively insensitive and operator depending. We assessed the diagnostic accuracy of a nephelometric assay for k free light chain determination in cerebrospinal fluid and serum. The patients were grouped according to clinical and laboratory criteria. ROC curves for all methods were performed to find the best cut-off value. kFLC Index seems to be more accurate than other parameters. Our data indicate that nephelometric assay for kFLCs in CSF reliably detect intrathecal immunoglobulin synthesis and discriminate multiple sclerosis patients.

Keywords: CNS; CSF; CSF/serum ratio of albumin; FLC; Ig; MS; Multiple Sclerosis; Multiple sclerosis; Nephelometry; OCBs; Q(alb); central nervous system; cerebrospinal fluid; free light chain; immunoglobulin; kFLC Index; kFLCs; oligoclonal immunoglobulin bands.

Publication types

  • Validation Study

MeSH terms

  • Adult
  • Aged
  • Biomarkers / blood
  • Biomarkers / cerebrospinal fluid
  • Female
  • Humans
  • Immunoglobulin kappa-Chains / biosynthesis*
  • Immunoglobulin kappa-Chains / blood
  • Immunoglobulin kappa-Chains / cerebrospinal fluid*
  • Injections, Spinal
  • Male
  • Middle Aged
  • Multiple Sclerosis / cerebrospinal fluid*
  • Multiple Sclerosis / diagnosis
  • Multiple Sclerosis / immunology*
  • Oligoclonal Bands* / biosynthesis
  • Oligoclonal Bands* / blood
  • Oligoclonal Bands* / cerebrospinal fluid
  • Reproducibility of Results
  • Severity of Illness Index
  • Young Adult


  • Biomarkers
  • Immunoglobulin kappa-Chains
  • Oligoclonal Bands