Table 1. Result comparison between 159 paired DBS and serum samples tested by the Luminex xMAPa and reference serologic assays for anti-SARS-CoV-2 antibodies.
| Roche ECLIA or Euroimmun ELISAb (Serum) | PPA (95% CI) | NPA (95% CI) | OC (95% CI) | Kappa (95% CI) | |||
| Positive | Negative | 96.1% (86–99.7%) | 97.2% (91.8–99.4%) | 96.9% (92.7–98.9%) | 0.928 (0.866–0.99) | ||
| Luminex xMAP (DBS)a | Positive | 49 | 3d | ||||
| Negative | 2c | 105 | |||||
Abbreviations: DBS, dried blood spot; PPA, positive percent agreement; NPA, negative percent agreement; OC, overall concordance.
aLuminex xMAP results on DBS were interpreted using manufacturer recommended MFI criteria for serum/plasma.
b139 sera were tested by the Roche ECLIA and 20 sera were tested by the Euroimmun ELISA.
cOne sample had sufficient serum for discordant sample analysis using the Ortho-Clinical Diagnostic anti-SARS-CoV-2 IgG CIA and resulted as ‘positive’.
dOne sample had sufficient serum for discordant analysis using the Ortho-Clinical Diagnostics anti-SARS-CoV-2 IgG CIA and resulted as ‘negative’.