Figure 2.

(a) Log-normalized antibody concentrations ln(${\widehat{c}}_{s,n,r}$), normalized to the WHO IS for 38 positive convalescent serum samples determined by the six different serological IgG assays labeled as Labs 1–6; (b) log-harmonized antibody concentrations $H_{s,r}$ shows a greater concordance with ln(c_s,r), shown as red squares; and (c) assay- and sample-dependent uncertainties, $-\Delta g_{s,n}+{\delta }_{s,n}$, which reflect the randomness of each individual’s sample–assay interaction.