Table 1.

Commercial assays employed in the study to identify IgG anti-SARS-CoV-2 antibody levels

Test	Manufacturer	Recognised antigen	Method	Manufacturers’ thresholds
LIAISON® SARS-CoV-2 S1/S2 IgG	DiaSorin	S1/S2	CLIAa	Negative: <12.0 AU/mL Equivocal: 12.0 ≤ × <15.0 AU/mL Positive: ≥15.0 AU/mL
Elecsys® Anti-SARS-CoV-2	Roche	N	ECLIAb	Positive: <1.0 Negative: ≥1.0
ARCHITECT® SARS-CoV-2 IgG	Abbott	N	CMIAc	Negative: <1.4 Positive: ≥1.4
LIAISON® SARS-CoV-2 TrimericS IgG	DiaSorin	Trimeric S	CLIAa	Negative: <33.8 BAU/mL Positive: ≥33.8 BAU/mL

CLIA chemiluminescent immunoassay, ECLIA electrochemiluminescent immunoassay, CMIA chemiluminescent microparticle immunoassay, AU arbitrary concentration units, BAU binding antibody unit