BACKGROUND: High serum concentrations of monoclonal free light chain (FLC) kappa or lambda are markers of plasma cell dyscrasia. METHODS: We developed new, latex-enhanced, specific nephelometric assays based on monoclonal antibodies for the determination of FLC kappa and lambda in serum, EDTA plasma and Li-heparin plasma for use on the Siemens BN™ systems. RESULTS: Reference ranges were determined from 369 samples: FLC kappa 6.7-22.4 mg/L, FLC lambda 8.3-27.0 mg/L and kappa/lambda ratio 0.31-1.56. Protection from falsely low results due to antigen excess is obtained with a built-in pre-reaction in the assay protocols. Lot-to-lot consistency between three different lots of reagent, calibrators and supplementary reagent lots showed normalized differences <7.5%. The reproducibility of serum samples varied between 4% and 7%. The method comparison with Freelite™ assays showed normalized differences of 19.7%, 32.7% and 21.7%, respectively, for FLC kappa, lambda and ratio, correlations of 0.94, 0.77 and 0.73, and concordance rates of 99.2%, 94.2% and 95%. CONCLUSIONS: N Latex FLC demonstrates high precision, good lot-to-lot consistency and freedom from a high-dose hook effect. The method comparison between Freelite™ and the N Latex FLC assays showed good clinical concordance. Further studies need to reveal the clinical value of the new FLC assays.
BACKGROUND: High serum concentrations of monoclonal free light chain (FLC) kappa or lambda are markers of plasma cell dyscrasia. METHODS: We developed new, latex-enhanced, specific nephelometric assays based on monoclonal antibodies for the determination of FLC kappa and lambda in serum, EDTA plasma and Li-heparin plasma for use on the Siemens BN™ systems. RESULTS: Reference ranges were determined from 369 samples: FLC kappa 6.7-22.4 mg/L, FLC lambda 8.3-27.0 mg/L and kappa/lambda ratio 0.31-1.56. Protection from falsely low results due to antigen excess is obtained with a built-in pre-reaction in the assay protocols. Lot-to-lot consistency between three different lots of reagent, calibrators and supplementary reagent lots showed normalized differences <7.5%. The reproducibility of serum samples varied between 4% and 7%. The method comparison with Freelite™ assays showed normalized differences of 19.7%, 32.7% and 21.7%, respectively, for FLC kappa, lambda and ratio, correlations of 0.94, 0.77 and 0.73, and concordance rates of 99.2%, 94.2% and 95%. CONCLUSIONS: N Latex FLC demonstrates high precision, good lot-to-lot consistency and freedom from a high-dose hook effect. The method comparison between Freelite™ and the N Latex FLC assays showed good clinical concordance. Further studies need to reveal the clinical value of the new FLC assays.
Authors: David Zeman; Pavlína Kušnierová; Zdeněk Švagera; František Všianský; Monika Byrtusová; Pavel Hradílek; Barbora Kurková; Olga Zapletalová; Vladimír Bartoš Journal: PLoS One Date: 2016-11-15 Impact factor: 3.240
Authors: Jennifer L J Heaney; John P Campbell; Punit Yadav; Ann E Griffin; Meena Shemar; Jennifer H Pinney; Mark T Drayson Journal: BMC Nephrol Date: 2017-07-20 Impact factor: 2.388
Authors: Punit Yadav; Paul Cockwell; Mark Cook; Jennifer Pinney; Hannah Giles; Yu Sandar Aung; David Cairns; Roger G Owen; Faith E Davies; Graham H Jackson; J Anthony Child; Gareth J Morgan; Mark T Drayson Journal: BMC Nephrol Date: 2018-07-13 Impact factor: 2.388
Authors: Klaus Berek; Gabriel Bsteh; Michael Auer; Franziska Di Pauli; Astrid Grams; Dejan Milosavljevic; Paulina Poskaite; Christine Schnabl; Sebastian Wurth; Anne Zinganell; Thomas Berger; Janette Walde; Florian Deisenhammer; Harald Hegen Journal: Neurol Neuroimmunol Neuroinflamm Date: 2021-05-28