The Abbott IgM-band had poor sensitivity within the first week of infection (0.00%), which did not improve much even after 2 weeks (PPA 2.78% (95% CI 0.07 to 14.5) ≥14 days POS), with a total sensitivity of 3.01% (95% CI 0.83 to 7.52) (see Supplementary Table 2). Here, CD40LG is linked to infection.