Related Experiment Video
Updated: May 3, 2026

Assessment of Human Natural Killer Cell Events Driven by FcγRIIIa Engagement in the Presence of Therapeutic Antibodies
Published on: May 22, 2020
The analytical performance evaluation of Freelite™ Human Kappa Free and Human Lambda Free on the SPAPLUS™
Kyong-Ho Cha1, Yang Bo Sim, Hyojin Chae
1Department of Laboratory Medicine, Seoul St. Mary's Hospital, The Catholic University of Korea.
Background:
SPAPLUS™ is a turbidimetric immunoassay analyzer for detection of excess free light chain (FLC) antigens in serum. Here, we evaluated the analytical performance of Freelite™ Human Kappa Free and Lambda Free on a SPAPLUS™ instrument.
Methods:
We evaluated the precision, linearity, sample carryover, and drift of the SPAPLUS™ instrument and compared it with Hitachi 7600 and BN™ II instruments. We evaluated the detection of antigen excess for 12 specimens from patients with monoclonal gammopathy.
Results:
The coefficients of variations of κFLC and λFLC were below 5.0%. Linearity was shown in the range of 9.68-152.25 mg/l for κFLC and 4.96-171.09 mg/l for λFLC, and no drift was observed. The κFLC sample carryover was statistically significant, but much smaller than the optimum allowable bias. Agreement rates with the two comparative methods were 87.1, 87.1, and 97.1% or higher for κFLC, λFLC, and the κ/λ ratio, respectively. Antigen excess signals were observed for all 12 antigen excess specimens.
Conclusions:
The Freelite™ on the SPAPLUS™ exhibited appropriate precision, linearity, and relative comparability to the reagents on the other instruments. It was good at detecting specimens that had previously demonstrated the hook effect due to antigen excess.
More Related Videos
08:22Calibration-free In Vitro Quantification of Protein Homo-oligomerization Using Commercial Instrumentation and Free, Open Source Brightness Analysis Software
Published on: July 17, 2018
08:26The Isolation, Differentiation, and Quantification of Human Antibody-secreting B Cells from Blood: ELISpot as a Functional Readout of Humoral Immunity
Published on: December 14, 2016