Fig. 3
From: RT-PCR negative COVID-19
Signal to cut-off ratio of A IgG and B IgM among pre-pandemic samples collected before 2019, RT-PCR and no clinical suspicion of COVID-19 (Non suspects), RT-PCR negative with clinical signs/symptoms of COVID-19, with no potential alternate diagnosis (Probables) and with alternate diagnosis (Suspects) and matched RT-PCR confirmed for COVID-19. Boxplot indicates the interquartile range as the box and the minimum and maximum values as whiskers. Dashed line indicates cut-off values for call for reactivity. Filled circles are individuals who received COVID-19 directed therapies. Comparison between groups were by two-sided Wilcoxon signed rank test. P1 > p-value between PCR-confirmed and Probables, P2 > p-value between Probables and Suspects, P3 > p-value between Non-suspects and Probables and P4 > p-value between Pre-pandemic and Probables