EliA SARS-CoV-2-Sp1 IgG: The
EliA SARS-CoV-2-Sp1 IgG (Thermo Fisher S1 IgG) is a fluoroenzyme-immunoassay (FEIA) for the in vitro quantitative measurement of IgG antibodies in human serum and plasma directed to the S1 protein [24] , performed on the
Phadia 250 instrument (Thermo Fisher, Uppsala, Sweden). The
EliA SARS-CoV-2-Sp1 IgG wells are coated with recombinant SARS-CoV-2 S1 protein.
After washing non-bound antibodies, enzyme-labelled anti-human IgG are added to form antibody-conjugate complexes incubated with a development solution. After stopping the reaction, the fluorescence in the reaction mixture is measured. The cut-off value in AU/mL, the conversion factor to obtain BAU/mL, the cut-off value in BAU/mL and the linearity range in AU/mL are respectively: 7.0, 4.0, 28 and 0.7-204, as declared by the manufacturer. Samples with values above 204 AU/ mL (816 BAU/mL) were diluted and measured 1:2 allowing the extension of the dynamic range up to 408 AU/mL (1,632 BAU/mL). According to the manufacturer, intra-and inter-assay precision data ranges between 2.1 and 3.1%; clinical specificity is 99.7% (95% CI: 98.4-100%) and clinical sensitivity is 100% (95% CI: 99.5-100%), calculated at eight days or more, after the first positive PCR.
Infantino M., Manfredi M., Stacchini L., Cosma C., Grossi V., Lari B., Russo E., Amedei A., Benucci M., Veneziani F., Casprini P., Catalano C.M., Cirrincione G., Bonaccorsi G, & Pompetti A. (2022). The role of neutralizing antibodies by sVNT after two doses of BNT162b2 mRNA vaccine in a cohort of Italian healthcare workers. Clinical chemistry and laboratory medicine, 60(6).
