Related Experiment Video
Updated: May 12, 2026
Simultaneous Detection of Different Antibody Classes in a Multiplexed Serological Test
Published on: July 14, 2023
A multicentre study comparing two methods for serum free light chain analysis
R J Lock1, R Saleem, E G Roberts
1Immunology and Immunogenetics, Pathology Sciences, North Bristol NHS Trust, Southmead Hospital, Westbury-on-Trym, Bristol BS10 5NB, UK. Robert.lock@nbt.nhs.uk
Background:
Serum free light chain analysis is now well established in the investigation of monoclonal gammopathies. In the UK there has, until recently, been a single supplier of kits for such analysis. Recently, a second method using monoclonal antisera was introduced. We have compared the performance of these two kits in four routine laboratories.
Method:
Samples submitted for routine analysis (327 samples, 258 [79%] from patients with B-cell lymphoproliferative disease) for serum free light chains were tested by both technologies (Freelite, Binding Site and N Latex FLC, Siemens), according to the manufacturers' instructions.
Results:
Qualitative data were available by both methods on 313 samples for serum free kappa chains and 324 samples for lambda free light chains. We found poor correspondence of 81% for kappa and 74% for lambda. Five percent of samples were significantly discordant in these assays.
Conclusions:
These assays perform very differently in clinical practice. They cannot be used interchangeably, especially if monitoring patient responses to therapy.
