N Latex FLC kappa and N Latex FLC lambda AssaysAdd consistency to monoclonal gammopathy testing

Free light chain (FLC) kappa and lambda Assays for use on Atellica® NEPH 630,* BN™ II, and BN ProSpec® Systems are designed for more reliable management of patients with monoclonal gammopathies. Excellent/stable lot-to-lot reproducibility leads to improved diagnostic accuracy as well as the sensitive detection of changes in follow-up testing.

Add confidence to screening and monitoring of monoclonal gammopathies with N Latex FLC kappa and N Latex FLC lambda Assays:

  • High specificity based on monoclonal antibodies
  • Excellent lot-to-lot reproducibility
  • Pre-reaction protocol ensures high antigen-excess security
  • Flexible kit design: reagents, supplementary reagent, standard, and controls are available separately and can be freely combined

Features & Benefits

Consistent Results Help Refine Disease Management Strategies
Determination of free light chains (FLC) has been part of the officially recommended screening panel for multiple myeloma since 2009.1,2 Furthermore, FLC determination helps in monitoring therapy success. Reliable results are a prerequisite for consistently high sensitivity in screening and sensitive detection of changes in follow-up. Studies have shown the clinical concordance of the N Latex FLC Assays to competitive assays.3,4
How Can Improved Lot-to-Lot Reproducibility and Antigen-excess Security Improve the Management of Patients with Monoclonal Gammopathy?

The N Latex FLC kappa and N Latex FLC lambda Assays offer a convenient way to determine free light chains on Siemens Healthineers automated immunonephelometric systems.

Excellent lot-to-lot consistency

  • Adds consistency to patient results and the follow-up of patients using different reagent lots.
  • Allows patient screening and monitoring of therapy, e.g., for myeloma patients.
  • Ensures improved patient management by early recognition of a potential relapse or resulting therapy adjustments – this may lead to an overall improved patient outcome.

Improved antigen-excess security

  • Feel more confident through detection of high-dose hook effects.
  • Improve cost-effectiveness due to fewer dilution steps.

Convenient packaging concept

  • Reduce costs with flexible, reagent-independent packaging. All components can be ordered separately, so you can ensure an adequate supply of standard and controls while eliminating waste.
  • Add confidence to screening and monitoring of monoclonal gammopathies with assays and systems from Siemens Healthineers.

Clinical Use

Comparison of immunoassays to immunofixation electrophoresis (IFE), number of abnormal results:

IFE, kappa Positive

N Latex FLC kappa Assay



60 (100%)

59 (98.3%)

IFE, lambda Positive

N Latex FLC lambda Assay



60 59 (98.3%)

56 (94.9%)

IFE, kappa and/or lambda Positive

N Latex FLC Ratio



105 (91.3%)

103 (89.6%)

Comparison of N Latex FLC Assay and FREELITE FLC assay

(n = 1118, categorized as abnormal low, normal, abnormal high):

(Reference: LD OUS N Latex FLC Add consistency to monoclonal gammopathy White Paper)


Agreement rate

Cohen’s coefficient

FLC kappa



FLC lambda



FLC ratio



FLC ratio method comparison
Lot to Lot Comparison Graph

Comparison of three independent reagent lots, including two different (lot-independent) standard lots (n = 95)

Reference: Velthuis et al. 2011: N Latex FLC – new monoclonal-based assays for FLC. Clin Chem Lab Med 2011;49(8):1323–1332 (literature number 3)

Technical Specifications

Analytical Assay Performance

Assay principle

Latex-enhanced immunonephelometry

Sample type

Human serum, EDTA plasma, heparinized plasma

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

3.4–110 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 – ≥ 9,000 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


Repeatability: < 5%
Within-lab: < 6.5%

Antigen-excess security

FLC kappa: up to 27,100 mg/L
FLC lambda: up to 57,300 mg/L