CD40LG and COVID-19: The pooled estimates for sensitivity and specificity of IgM to predicting COVID-19 diagnosis were 0.71 (95% CI: 0.69–0.72) and 0.93 (95% CI: 0.92–0.93), respectively, (Figure 2), corresponding to a PLR of 20.40 (95% CI: 11.71–35.55) (Appendix 5) and an NLR of 0.33 (95% CI: 0.25–0.42) (Appendix 6).