2.6. Statistical analysis

To compare Biolidics and ELISA in detecting antibodies at D0 and D7, we first calculated the sensitivity for different scenarios. Then, to control for possible confounding factors, we focused on the 10 positive samples by PCR analysis that have test results available with both techniques, by conducting a paired two-sample t-test (Table 3). Paired two-sample t-test was also conducted to compare plasma and whole blood samples with Biolidics (Table 4B). Exact 95% confidence intervals (Clopper–Pearson Method for Binomial Proportions) of percentage positivity for anti-SARS-CoV-2 IgM and IgG were calculated in patients with SARS-CoV-2 assessed by Biolidics (Table 1B) and in patients with SARS-CoV-2 assessed by ELISA (Table 2B). The sensitivity of IgM and IgG detection with capillary samples in patients with SARS-CoV-2 was also calculated (Table 4D). P-values lower than 0.05 were considered statistically significant. The calculations were performed using R software.

Specificity of IgM and IgG detection by Biolidics in patients without SARS-CoV-2.^a

Specificity of IgM and IgG detection by ELISA in patients without SARS-CoV-2.^a

Comparison of Biolidics and ELISA in detecting antibodies at D0 and D7.^a

- p-value is calculated via paired t-test; p-value <0.05 is considered statistically significant.

Comparison of plasma and whole blood samples in detecting IgM and IgG with Biolidics.

- p-value <0.05 is considered statistically significant.

Sensitivity of capillary samples in detecting IgM and IgG with Biolidics >14 days after symptom onset.^a