Table 6.

Table showing the Linear Regression Conversion Models to calibrate to WHO IS units and then assay linearity range for extrapolating concentrations.

Antibody	Linear Regression Model (BAU Conversion Model)	Linearity Range (ng/ml)	CV % Range	Adjusted R2
S-IgG	Conc BAU/ml = 0.080429 + 0.018729 * Conc ng/ml	100 – 1.0	14.38% - 7.26%	1.00
S-IgM	Conc BAU/ml = 0.465119 + 0.036897 * Conc ng/ml	1000 – 0.320	16.40% - 0.17%	0.9964
S-IgA	Conc BAU/ml = -0.035959 + 0.190851 * Conc ng/ml	1000 – 8.0	18.82% - 0.08%	0.9944
N-IgG	Conc BAU/ml = 0.252450 + 0.011651 * Conc ng/ml	100 – 1.0	21.33% - 0.33%	0.9999
N-IgM	Conc BAU/ml = -1.808749 + 0.615273 * Conc ng/ml	1000 – 1.6	8.22% - 0.42%	0.9998
N-IgA	Conc BAU/ml = 0.378230 + 0.622280 * Conc ng/ml	1000 – 8.0	17.39% - 0.09%	0.9953
RBD-IgG	Conc BAU/ml = 0.834818 + 0.025888 * Conc ng/ml	1000 – 10.0	6.13% - 0.37%	0.9999
RBD-IgM	Conc BAU/ml = 0.539426 + 0.031529 * Conc ng/ml	1000 – 1.6	12.32% - 0.04%	0.9980
RBD-IgA	Conc BAU/ml = 0.053400 + 0.491130 * Conc ng/ml	1000 – 10.0	6.22% - 0.13%	0.9999

Table 6 shows the linear Conversion models (column 2) for each of the antibodies. For S-IgG, the linear model is Conc (in BAU/ml) = 0.080429 + 0.018729 * Conc (in ng/ml). This implies given a spike IgG Concentration of 1000 ng/ml, the above linear model can be used to get the equivalent spike IgG Concentration in BAU/ml as 0.080429 + 0.018729 * 1000 = 18.80943 BAU/ml. Columns 3, 4 and 5 show that linearity rages were achieved for all antibodies, their associated %CV and coefficient of determination (R²) are indicated.