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Summary:

  • There are currently five external quality assurance schemes for sFLC analysis, and one scheme for Hevylite® analysis.
  • The UK NEQAS scheme has the highest number of participants, with over 380 laboratories registered.
  • When submitting sFLC results as part of an external quality assurance scheme it is important to treat the sample as routine (including antigen excess checks) and ensure that concentrations are reported using the correct units.

It is important that all laboratories participate in external quality assurance (QA) schemes when performing monoclonal protein analysis. There are several national and international QA schemes for assessing serum free light chains (sFLC). Particular care should be taken when reporting sFLC results: in the USA mg/dL units are commonly used, while elsewhere, mg/L is the norm. Individual QA scheme results that are 10- or 100-fold different from the majority view can probably be attributed to errors in calculating or recording the sample concentration.