[Analytical performances of SPAPLUS® turbidimeter for the dosage of immunoglobulins and beta-2 microglobulin in serum]. / Évaluation des performances analytiques du turbidimètre SPAPLUS® pour le dosage des immunoglobulines et de la bêta-2 microglobuline dans le sérum.

We evaluated the analytical performances of the SPAPLUS(®) immunoturbidimeter assays manufactured by The Binding Site(®) for the quantification of thirteen immunological parameters in serum: IgG, IgA, IgM and IgD immunoglobulins, IgG subclasses (1 to 4), IgA subclasses (1 and 2), beta-2 microglobulin, free light chains kappa and lambda. The within-day precision (repeatability) and the between-day precision (reproducibility) were obtained for two or three concentration levels depending of the parameter and were below the recommendations of the manufacturer, except for the repeatability of IgG1 (at a level of concentration of 6.7 g/L). An agreement above 90% (with Bland and Altman analysis) was observed between the results obtained with SPAPLUS(®) and those obtained with the nephelometer IMMAGE(®) 800 or radial immunodiffusion. The evaluation confirmed the linearity of the assays and the absence of contamination for all the parameters tested. We also assessed the practicability of the SPAPLUS(®) in terms of maintenance, frequency of calibration and cadence tests. The SPAPLUS(®) immunoturbidimeter displays good analytical performances for the immunological parameters evaluated in the present work.

Good performance of immunoglobulin M assays in diagnosing genotype 3 hepatitis E virus infections.

We have evaluated three anti-hepatitis E virus (anti-HEV) immunoglobulin M (IgM) assays, the EIAgen HEV IgM assay (Adaltis), the HEV IgM enzyme-linked immunosorbent assay 3.0, and the Assure HEV IgM rapid test (MP Diagnostics), for the routine detection of acute genotype 3 HEV. Their sensitivities were fairly good (90%, 88%, and 82%), and their specificities were excellent (100%, 99.5%, and 100%).