FIG 4.

Relationship to and distribution of the LIAISON SARS-CoV-2 S1/S2 IgG assay levels versus NT dilutions. LIAISON SARS-CoV-2 S1/S2 IgG measurements were separated into 3 groups (<40 AU/ml, 40 to 80 AU/ml, and >80 AU/ml) and related to NT assay groups by titers: ≥1:160 (dark gray) or ≥1:80 (light gray). In the >80-AU/ml group, 33 of 38 samples have an NT assay titer of ≥1:160, while 35 of 38 samples have an NT assay titer of ≥1:80. Both titers are considered acceptable by FDA guidelines (12). The respective semiquantitative groups contain 43, 43, and 38 samples.