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  5. N Latex FLC kappa and N Latex FLC lambda Assays

N Latex FLC kappa and N Latex FLC lambda AssaysThe first immunoassay with clearance for evaluation of monoclonal gammopathies of undetermined significance (MGUS).1,2

N Latex Free Light Chain (FLC) kappa and lambda assays enable more-reliable management of patients with monoclonal gammopathies. Designed for use on nephelometric Atellica® NEPH 630* and BN™ Systems, these high-sensitivity assays provide:

  • Concordance with IMWG recommendations and other international guidelines
  • A single reference range independent of patients’ kidney status
  • Reliable results without possible value drift over time due to use of monoclonal antibodies and lot-to-lot consistency
  • One kit for all sample types: serum, plasma, urine, and CSF
N Latex FLC kappa and N Latex FLC lambda Assays

Benefits

Unique monoclonal antibodies

Monoclonal antibodies provide significant advantages in analytical performance:

  • Higher consistency in results obtained from different reagent lots enables early detection of changes in disease activity and subsequent adjustments to therapy, and ultimately contributes to improved patient management and outcomes.
  • In research studies, monoclonal FLC assays produced no false-positive κ/λ ratios in patients with renal impairment.3-5 In comparison, the false-positive rate of polyclonal FLC assays in patients with renal impairment was 8–36%.6,7
One reference range for all patients

Free light chain assay results might be affected by patients' kidney status. The iStopMM study revealed inaccuracies in reference intervals and ratios for a commonly used assay.8

Avoid potential patient misclassification with N Latex FLC assays:

  • Simplifies identification of patients with monoclonal gammopathies with one clear, easy-to-interpret reference range for all patients, including those with impaired renal function.
  • Minimizes the risk of patient misclassification due to human error and/or initial patient misclassification.
  • Helps avoid unnecessary referrals and unnecessary invasive diagnostics.
  • Supports more-accurate monitoring of response to therapy and allows better comparison of FLC data obtained from FLC assays in different clinical trials.
High specificity

High clinical specificity enables clinicians to confidently identify patients not affected by monoclonal disease.

  • High specificity helps prevent misdiagnosis of malignant disorders in non-affected individuals.
  • Universal reference range independent of renal impairment simplifies result interpretation.
  • Correlation of the FLC kappa/lambda ratio produced by N Latex FLC assay is accurate for samples at both high- and low-end concentrations vs. the ratio produced by the FREELITE assay, which can be severely affected as shown in the graph above.
Nephelometric technology for confidence in results

Nephelometry offers analytical advantages over turbidimetry in terms of precision and sensitivity, including antigen-excess security, for confidence in results. N Latex FLC kappa and lambda assays:

  • Use built-in pre-reaction protocols for detection of antigen excess. 
  • Provide more-consistent results.
  • Generate fewer false-low test results, even in samples with very high FLC concentrations. 
  • Reduce the need for costly reruns.

Nephelometry has been recommended by the IMWG and ESMO guidelines for use with FLCs and immunoglobulins respectively.

Cost-efficient packaging

N Latex FLC assay components help labs reduce costs with flexible, reagent-independent packaging.

All N Latex FLC components can be ordered separately, so you can ensure an adequate supply of standard and controls while eliminating waste.

Unique monoclonal antibodies

Monoclonal antibodies provide significant advantages in analytical performance:

  • Higher consistency in results obtained from different reagent lots enables early detection of changes in disease activity and subsequent adjustments to therapy, and ultimately contributes to improved patient management and outcomes.
  • In research studies, monoclonal FLC assays produced no false-positive κ/λ ratios in patients with renal impairment.3-5 In comparison, the false-positive rate of polyclonal FLC assays in patients with renal impairment was 8–36%.6,7

FLC testing in MGUS evaluation

FLC testing in MGUS evaluation

Evaluation of monoclonal gammopathies of undetermined significance (MGUS) is very important as it is seen as a precursor to multiple myeloma. Early detection of multiple myeloma facilitates early treatment with a higher patient survival rate.

Learn more about MGUS and progression to multiple myeloma.

Technical Details

Analytical specifications for Atellica NEPH 630 and BN Systems

Assay principle

Latex-enhanced immunonephelometry

Sample type

Human serum, EDTA plasma, heparinized plasma†, CSF†, urine†

Reference range

FLC kappa: 6.7–22.4 mg/L

FLC lambda: 8.3–27.0 mg/L

FLC ratio: 0.31–1.56

Initial measuring ranges

3.5–110 mg/L for FLC kappa

1.9–60 mg/L for FLC lambda

Total measuring range

0.17–≥2,000 mg/L for FLC kappa

0.47–≥6,000 mg/L for FLC lambda

Measuring time

12 minutes

Onboard reagent stability

2 weeks (Atellica NEPH 630* and BN ProSpec Systems)

5 days (6 days with evaporation stoppers) on BN II System

Calibration frequency

6 weeks

Precision

Repeatability: <5%

Within-lab: <6.5%

Antigen-excess security

FLC kappa: up to 23,000 mg/L

FLC lambda: up to 57,000 mg/L

Downloads

*
Not available for sale in the U.S. Product availability varies by country.
†
Applications are not available in the U.S.
1
510(k) Substantial Equivalence Determination Decision Memorandum, 510(k) Number K150658 for The Binding Site Group, Ltd.
2
510(k) Substantial Equivalence Determination Decision Memorandum, 510(k) Number K193047 for Siemens Healthcare Diagnostics Products GmbH.
3
Jacobs, et al. Clin Chem Lab Med. 2014. Available from: https://www.degruyter.com/document/doi/10.1515/cclm-2013-0864/html
4
Rindlisbacher, et al. J Applied Lab Med. 2020. Available from: https://academic.oup.com/jalm/article/5/1/114/5610510
​5
Sprangers, et al. Kidney Int Rep. 2020. Available from: https://www.kireports.org/article/S2468-0249(20)30040-1/fulltext
6
Hutchison, et al. BMC Nephrol. 2008;9:11. Available from: https://bmcnephrol.biomedcentral.com/articles/10.1186/1471-2369-9-11
7
Molinar-Andujar, et al. BMC Nephrol. 2020;21:111 Available from: : https://doi.org/10.1186/s12882-020-01771-3
8
Long TE, et al. Defining new reference intervals for serum free light chains in individuals with chronic kidney disease: Results of the iStopMM study. Blood Cancer J. 2022 Sep 14;12(9):133. 
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