Overestimation of free light chain antigen excess rate

Vercammen, Martine; Broodtaerts, Linda; Meirlaen, Patricia; Bossuyt, Xavier

doi:10.1016/j.cca.2015.02.047

Cited by 7 publications

(6 citation statements)

References 13 publications

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“…Similar to previous reports (Hansen et al 2012 ; te Velthuis et al 2011 ), these data suggest that plasma is an acceptable specimen for free light chain analysis. The precision, linearity, and analyte stability in plasma is also comparable to that described for serum in previous publications (Altinier et al 2013 ; Briand et al 2010 ; Cha et al 2014 ; Hansen et al 2012 ; Pretorius et al 2012 ; Tate et al 2003 , 2009 ; Vercammen et al 2015 ).…”

Section: Discussionsupporting

confidence: 85%

“…These dilutions offer potential for error. At high concentrations of free light chains, antigen excess is also possible (Bosmann et al 2010 ; Vercammen et al 2015 ). We did not study antigen excess in detail but did observe comparable results with both plasma specimen types in a patient previously observed to have hook effect with lambda concentrations.…”

Section: Discussionmentioning

confidence: 99%

“…We did not study antigen excess in detail but did observe comparable results with both plasma specimen types in a patient previously observed to have hook effect with lambda concentrations. Specimens with very low values of kappa or lambda can also lead to higher variability in the kappa/lambda ratio, especially with the high imprecision typical of analyses in these low concentration ranges (Altinier et al 2013 ; Briand et al 2010 ; Cha et al 2014 ; Hansen et al 2012 ; Pretorius et al 2012 ; Tate et al 2003 , 2009 ; Vercammen et al 2015 ).…”

Section: Discussionmentioning

confidence: 99%

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Effect of specimen type on free immunoglobulin light chains analysis on the Roche Diagnostics cobas 8000 analyzer

et al. 2015

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The measurement of free immunoglobulin light chains is typically performed on serum; however, the use of alternative specimen types has potential benefits. Using the Freelite™ kappa and lambda free light chains assay on a Roche Diagnostics cobas 8000 c502 analyzer, we compared three specimen types (serum, EDTA-plasma and lithium heparin plasma separator gel-plasma) on 100 patients. Using Deming regression and eliminating outliers (limiting data to light chain concentrations below 400 mg/L), the three specimen types showed comparable results for kappa light chain concentration, lambda light chain concentration, and kappa/lambda ratio with slopes close to 1.0 and y-intercepts close to zero. EDTA-plasma showed slightly more positive bias relative to serum than lithium heparin. Analysis using EDTA-plasma and lithium heparin plasma showed comparable linearity, precision, and temperature stability. A single sample showing hook effect (not in the comparison set) gave comparable results using either plasma specimen type. For the Freelite™ kappa and lambda free light chains assay, both EDTA-plasma or lithium heparin-plasma can serve as acceptable substitutes for serum, at least for the Roche cobas 8000 analyzer.

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Section: Discussionsupporting

confidence: 85%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Effect of specimen type on free immunoglobulin light chains analysis on the Roche Diagnostics cobas 8000 analyzer

et al. 2015

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“…This method uses rabbit polyclonal antibodies against free j or k light chains in the capture phase, and rabbit polyclonal horse radish peroxidase-conjugated antibodies directed against j or k light chains, which are nonspecific for FLC, for detection. Calibrators were obtained from pooled human sera containing polyclonal FLC [63][64][65]. The Sebia assays were validated on the automated ELISA processor AP22 ELITE [66].…”

Section: Assays For Quantification Of Serum Free Light Chainsmentioning

confidence: 99%

“…As expected for polyclonal antisera, with the Freelite reagent, assay imprecision due to lot-to-lot variations emerged [70], particularly at low concentrations [65]. Currently, the problem has been partially overcome [71].…”

Section: Assay Limitationsmentioning

confidence: 99%

Inter-assay variability in automated serum free light chain assays and their use in the clinical laboratory

Caponi

Romiti

Koni

et al. 2019

Critical Reviews in Clinical Laboratory Sciences

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Serum j and k free light chain levels are markers of plasma cell proliferation, and their measurements have been included in recent guidelines by the International Myeloma Working Group for the management of patients with plasma cellular dyscrasias. Five in vitro diagnostic methods for the immunochemical quantification of serum free light chains (FLC) are available, three based on polyclonal antibodies (Freelite V R , The Binding Site; FLC ELISA j and k, Sebia; human j and k FLC, Diazyme Laboratories) and two on monoclonal antibodies (N Latex FLC, Siemens Healthineers; Seralite V R , Sebia). Several studies have shown that these methods cannot be used interchangeably for the follow-up of patients because measured j and k FLC concentrations may differ significantly, especially at high levels. Because no international reference material for the measurement of FLC is available, it is not possible to establish which method is the most accurate. For this reason, knowledge about the analytical and diagnostic performances of the assays used is important. The aim of this review is to describe the main analytical features of the j and k FLC assays and how they may influence the clinical use of these parameters.

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Evaluation of the new Sebia free light chain assay using the AP22 ELITE instrument

Lutteri

Aldenhoff

Cavalier

2018

Clinica Chimica Acta

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Overestimation of free light chain antigen excess rate

Cited by 7 publications

References 13 publications

Effect of specimen type on free immunoglobulin light chains analysis on the Roche Diagnostics cobas 8000 analyzer

Effect of specimen type on free immunoglobulin light chains analysis on the Roche Diagnostics cobas 8000 analyzer

Inter-assay variability in automated serum free light chain assays and their use in the clinical laboratory

Evaluation of the new Sebia free light chain assay using the AP22 ELITE instrument

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