Analytical and clinical concordance of free light chain assay

摘要

The analysis of serum for the presence of free light chains has become an important adjunct to testing by serum proteinelectrophoresis (SPE) and immunofixation electrophoresis (IFE) [1]. The first commercial free light chain assays using polyclonalreagents was released in 2001 by Binding Site Inc. (Freelite?). Subsequently, in 2011, Siemens released monoclonal-based free lightchain assays. The interest in free light chain testing has increased with a more than doubling of the subscription rates to the Collegeof American Proficiency Testing Survey from 2010. We validated the Diazyme free light chain assay, a latex particle enhancedimmunoturbidimetric assay that uses polyclonal antibodies and was adapted to the Siemens Advia 1800 analyzer. As this assay wasnot FDA approved on this analyzer, we considered it as a “lab developed test.” We conducted a clinical concordance study comparedto the Freelite assay as the predicate.