Evaluation of the Novel Hevylite Immunoassay (HLC) in the Quantification of Monoclonal Proteins in Monoclonal Gammopathies.

Abstract

Quantification of the monoclonal protein (M-protein) in monoclonal gammopathies is crucial for correct diagnosis, management, and prognosis. When the M-protein concentration is less than 10 g/L, and it migrates to the β-fraction in electrophoresis, traditional laboratory quantification methods, such as serum electrophoresis (SPEP) become unreliable. The novel Hevylite immunoassay (HLC) allows for the quantitative determination of the specific pairs of heavy and light chains and could become useful for M-protein quantification in low concentration samples. The aim of this study is to compare HLC assay quantification of M-protein samples of less than 10 g/L migrating in the beta fraction in electrophoresis to other electrophoretic quantification techniques, using nephelometric total Ig quantification as the reference gold standard for protein quantification. For 112 serum samples meeting inclusion criteria, M-protein was quantified using perpendicular SPEP, tangential SPEP, HLC, and total immunoglobulin nephelometry. Using total immunoglobulin as the reference method, correlation coefficients and regression models were obtained for the other 3 methods of protein quantification. The data obtained in this study suggest that the quantification of low concentration M-protein migrating in the beta-fraction by Hevylite correlates and agrees more strongly with total immunoglobulin nephelometry when compared to electrophoretic quantification methods.