Fig 7: IgG test affords quantitative assessment of serum IgG from a single measurement.

(a) The relationship between the log-transformed readout value (A₄₅₀ at 1/1,000 serum dilution) in the IgG antibody test and the endpoint IgG titer (determined from full ELISA curves), for each serum sample in the Conv cohort. Data were fit to a sigmoidal function through a nonlinear regression analysis. (b) A ten-fold cross-validation method was used to evaluate the predictive utility of this model. For each serum sample, the experimentally determined endpoint IgG titer was compared to that predicted from a single measurement with the antibody test using linear regression analysis. Shaded blue areas represent the 95% confidence intervals for the curve fits.