Fig. 2.

GC-FP results for serum (A) and dried blood spot (B) samples from subjects with verified positive COVID-19 infection status. The difference between the average positive and negative GC-FP detection ratios was confirmed using the Mann-Whitney U test, with corresponding p values shown in each plot. ELISA (450 nm absorbance values) for the COVID-19 nucleocapsid protein were compared to GC-FP detection ratio results for a subset of serum samples (C), while Luminex MIA results (MFI values) were compared to GC-FP detection ratio results for a second subset of samples (D). Pearson correlation coefficients (r) and R-squared values from correlation are shown, with associated p-values. Dashed lines indicate linear regression fit to the data, while dotted lines indicate the 95% confidence intervals for correlation analysis.