FIGURE 5.

Immunoglobulin anti‐NP (IgM, and IgA, left; IgG right) S/CO according to ln nAb titers from 226 convalescent plasma with final RT‐PCR status. The horizontal and vertical long‐dashed lines on the right upper quadrant (IgG) denotes a proposed limit for both high IgG S/CO level (≥5.0; above the horizontal dashed line) and neutralizing antibody titer ≥160 (right of vertical dash line). Agreement between IgG S/CO ≥5.0 and neutralizing antibody ≥160 was 82.4%. There is a strong correlation between immunoglobulin levels (S/CO) and neutralizing antibody titers (ln), as measured by the Spearman's rho correlation coefficient (0.49, 0.66, and 0.54 for IgM, IgG, and IgA, respectively; all P < .01)