TABLE 1.
Information for the 4 SARS-CoV-2 IgG immunoassays used to test study samples
| Assay namea | Manufacturer | Method | Protein (antigen) target | Negative index | Positive index |
|---|---|---|---|---|---|
| Architect SARS-CoV-2 IgG | Abbott Laboratories Inc., Abbott Park, IL | CMIA | Nucleocapsid | <1.4 | ≥1.4 |
| Liaison SARS-CoV-2 S1/S2 IgG | DiaSorin Inc., Stillwater, MN | CIA | Spike 1 + spike 2 | <15.0 | ≥15.0 |
| Vitros anti-SARS-CoV-2 IgG | Ortho Clinical Diagnostics, Raritan, NJ | CIA | Spike 1 | <1.0 | ≥1.0 |
| Anti-SARS-CoV-2 ELISA (IgG) | Euroimmun Inc., Mountain Lakes, NJ | ELISA | Spike 1 | <0.8 | ≥0.8b |
a
For the CMIA and CIA methods, the assay name begins with the instrument utilized for test performance.
b
Per the Euroimmun instructions for use, index values of 0.8, 0.9, and 1.0 are considered equivocal; however, for the purposes of this study, equivocal results were interpreted as positive.