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Immunoglobulin Free Light Chains Kappa and Lambda Human ELISA

  • Regulatory status:RUO
  • Type:Sandwich ELISA, Biotin-labelled antibody
  • Other names:FLC
  • Species:Human
Cat. No. Size Price

RD194088100R 2x 96 wells(1 kit) $603
PubMed Product Details
Technical Data


Sandwich ELISA, Biotin-labelled antibody


Serum, Plasma-EDTA, Plasma-Heparin, Plasma-Citrate, Urine

Sample Requirements

2×5 µl/well


At ambient temperature. Upon receipt, store the product at the temperature recommended below.


Store the kit at 2–8°C. Under these conditions, the complete kit is stable until the expiration date (see label on the box).

Calibration Curve

Calibration Range

10–320 µg/l (FLC kappa)
17.5–560 µg/l (FLC lambda)

Limit of Detection

FLC kappa ELISA Limit of detection (LOD) (defined as concentration of analyte giving absorbance higher than mean absorbance of blank plus three standard deviations of the absorbance of blank: Ablank + 3×SDblank) is calculated from the real FLC kappa values in wells and is 6 μg/L.

FLC lambda ELISA Limit of detection (LOD) (defined as concentration of analyte giving absorbance higher than mean absorbance of blank plus three standard deviations of the absorbance of blank: Ablank + 3×SDblank) is calculated from the real FLC lambda values in wells and is 5 μg/L.

Intra-assay (Within-Run)

n = 8;
CV = 3.0% (FLC kappa)
CV = 4.5% (FLC lambda)

Inter-assay (Run-to-Run)

n = 6;
CV = 7.0% (FLC kappa)
CV = 6.4% (FLC lambda)

Spiking Recovery

101.4% (FLC kappa)
100.9% (FLC lambda)

Dilution Linearity

87.8% (FLC kappa)
85.8% (FLC lambda)


  • bovine Non-detectable
  • cat Not tested
  • goat Non-detectable
  • horse Non-detectable
  • dog Not tested
  • hamster Not tested
  • mouse Non-detectable
  • pig Non-detectable
  • rabbit Non-detectable
  • rat Non-detectable
  • sheep Non-detectable
  • chicken Not tested
  • monkey Not tested
  • human Yes


  • Intended for research use only.
  • The total assays time is less than 3.5 hours.
  • The kit measures FLC kappa and FLC lambda in serum, plasma and urine.
  • Components of the kit are provided ready to use, concentrated and lyophilized.
  • Calibrators and Quality Controls are human serum based.

Research topic

Autoimmunity, Oncology


Human immunoglobulin molecules consist of two identical heavy chains which define immunoglobulin classes (IgG, IgA, IgM, IgD and IgE) and identical light chains (kappa or lambda) that are covalently linked to a heavy chain. In healthy individuals, the majority of light chains in serum exist bound to heavy chain. However, low levels of free light chains (FLCs) are found in serum of normal individuals due to their excess production over heavy chains by mature B-cells. In serum, FLC kappa exists predominantly as a monomer with a molecular weight of 22.5 kDa and FLC lambda as a dimer with a molecular weight of 45 kDa. This size difference results in a differential glomerular filtration rate and, consequently, a ratio of FLC kappa to FLC lambda of 1:1.6 in serum.

FLCs are observed in urine too but filtration and reabsorption of low molecular proteins in the kidney strongly affects the FLC concentration so that urinary FLC level is low in healthy individuals.

FLC are a natural product of B lymphocytes and, as such, represent a unique biomarker of neoplastic and reactive B cell-related disorders. Increased FLCs are associated with malignant plasma dyscrasia and other lymphocyterelated immunoproliferative disorders.

The detection of the FLCs is important diagnostic aid for a variety of monoclonal gammopathies, such as multiple myeloma, Waldenstrom macroglobulinemia, nonsecretory myeloma, smoldering multiple myeloma, monoclonal gammopathy of undetermined significance. Accurate measurement of monoclonal free light chains in serum and/or urine is especially important in light-chain diseases, such as light-chain myeloma, primary systemic amyloidosis, and light chain-deposition disease. The ability to quantify monoclonal FLCs may be useful to monitor the disease. In patients with light chain myeloma, either of light chain, kappa or lambda, is dominantly produced and resulting in marked changes of the FLC κ/λ ratio in the early phase of the disease. The detection of urinary monoclonal kappa or lambda free light chains of immunoglobulin, also know as Bence Jones proteins (BJP), are important for identifying and monitoring Bcell malignancies too.

In addition, compared with the healthy state, the synthesis of polyclonal FLC is markedly increased in conditions associated with B cell activation as found in certain inflammatory or autoimmune diseases (e.g. systemic lupus erythematosus, rheumatoid arthritis, or multiple sclerosis, as well as in cancer, diabetes mellitus, and AIDS).

Product References (7)


  • Tanimura K, Sato S, Sato A, Tanabe N, Hasegawa K, Uemasu K, Hamakawa Y, Hirai T, Muro S. Low serum free light chain is associated with risk of COPD exacerbation. ERJ Open Res. 2020 Jul 6;6(2):00288-2019. doi: 10.1183/23120541.00288-2019. eCollection 2020 Apr. PubMed PMID: 32665945. PubMed CentralPMCID: PMC7335835. See more on PubMed
  • Zeman D, Kušnierová P, Švagera Z, Všianský F, Byrtusová M, Hradílek P, Kurková B, Zapletalová O, Bartoš V. Assessment of Intrathecal Free Light Chain Synthesis: Comparison of Different Quantitative Methods with the Detection of Oligoclonal Free Light Chains by Isoelectric Focusing and Affinity-Mediated Immunoblotting. PLoS One. 2016 Nov 15;11(11):e0166556. doi: 10.1371/journal.pone.0166556. eCollection 2016. PubMed PMID: 27846293. PubMed CentralPMCID: PMC5112955. See more on PubMed
  • Cambridge G, Perry HC, Nogueira L, Serre G, Parsons HM, De La Torre I, Dickson MC, Leandro MJ, Edwards JC. The effect of B-cell depletion therapy on serological evidence of B-cell and plasmablast activation in patients with rheumatoid arthritis over multiple cycles of rituximab treatment. J Autoimmun. 2014 May;50:67-76. doi: 10.1016/j.jaut.2013.12.002. Epub 2013 Dec 22. PubMed PMID: 24365380. See more on PubMed
  • Franco DA, Truran S, Burciu C, Gutterman DD, Maltagliati A, Weissig V, Hari P, Migrino RQ. Protective role of clusterin in preserving endothelial function in AL amyloidosis. Atherosclerosis. 2012 Nov;225(1):220-3. doi: 10.1016/j.atherosclerosis.2012.08.028. Epub 2012 Sep 1. PubMed PMID: 22981431. PubMed CentralPMCID: PMC3478430. See more on PubMed
  • Yu HR, Kuo HC, Huang EY, Liang CD, Hwang KP, Lin IC, Sheen JM, Wang TJ, Wang CL, Yang KD. Plasma clusterin levels in predicting the occurrence of coronary artery lesions in patients with Kawasaki disease. Pediatr Cardiol. 2010 Nov;31(8):1151-6. doi: 10.1007/s00246-010-9769-7. Epub 2010 Aug 15. PubMed PMID: 20711835. See more on PubMed
  • Yu HR, Kuo HC, Sheen JM, Wang L, Lin IC, Wang CL, Yang KD. A unique plasma proteomic profiling with imbalanced fibrinogen cascade in patients with Kawasaki disease. Pediatr Allergy Immunol. 2009 Nov;20(7):699-707. doi: 10.1111/j.1399-3038.2008.00844.x. Epub 2009 Jan 12. PubMed PMID: 19170925. See more on PubMed
  • Beck ML, Freihaut B, Henry R, Pierce S, Bayer WL. A serum haemagglutinating property dependent upon polycarboxyl groups. Br J Haematol. 1975 Jan;29(1):149-56. doi: 10.1111/j.1365-2141.1975.tb01808.x. PubMed PMID: 32. See more on PubMed
Summary References (12)

References to Immunoglobulin Free Light Chains Kappa and Lambda

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  • Bradwell AR, Carr-Smith HD, Mead GP, Tang LX, Showell PJ, Drayson MT, Drew R. Highly sensitive, automated immunoassay for immunoglobulin free light chains in serum and urine. Clin Chem. 2001 Apr;47 (4):673-80
  • Drayson M, Tang LX, Drew R, Mead GP, Carr-Smith H, Bradwell AR. Serum free light-chain measurements for identifying and monitoring patients with nonsecretory multiple myeloma. Blood. 2001 May 1;97 (9):2900-2
  • Graziani M, Merlini G, Petrini C. Guidelines for the analysis of Bence Jones protein. Clin Chem Lab Med. 2003 Mar;41 (3):338-46
  • Jaskowski TD, Litwin CM, Hill HR. Detection of kappa and lambda light chain monoclonal proteins in human serum: automated immunoassay versus immunofixation electrophoresis. Clin Vaccine Immunol. 2006 Feb;13 (2):277-80
  • Katzmann JA, Clark RJ, Abraham RS, Bryant S, Lymp JF, Bradwell AR, Kyle RA. Serum reference intervals and diagnostic ranges for free kappa and free lambda immunoglobulin light chains: relative sensitivity for detection of monoclonal light chains. Clin Chem. 2002 Sep;48 (9):1437-44
  • Levinson SS, Keren DF. Free light chains of immunoglobulins: clinical laboratory analysis. Clin Chem. 1994 Oct;40 (10):1869-78
  • Nakano T, Nagata A. ELISAs for free light chains of human immunoglobulins using monoclonal antibodies: comparison of their specificity with available polyclonal antibodies. J Immunol Methods. 2003 Apr 1;275 (1-2):9-17
  • Nakano T, Nagata A, Takahashi H. Ratio of urinary free immunoglobulin light chain kappa to lambda in the diagnosis of Bence Jones proteinuria. Clin Chem Lab Med. 2004 Apr;42 (4):429-34
  • Rajkumar SV, Kyle RA, Therneau TM, Melton LJ 3rd, Bradwell AR, Clark RJ, Larson DR, Plevak MF, Dispenzieri A, Katzmann JA. Serum free light chain ratio is an independent risk factor for progression in monoclonal gammopathy of undetermined significance. Blood. 2005 Aug 1;106 (3):812-7
  • Robinson EL, Gowland E, Ward ID, Scarffe JH. Radioimmunoassay of free light chains of immunoglobulins in urine. Clin Chem. 1982 Nov;28 (11):2254-8
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