Table 2. Area under the receiver operating characteristic curve (AUC) for each commercial and in-house assay on dried blood spot specimens (DBS).
| Assay | DBS punches (n =) | AUCa (95% CI [LL, UL]) | P value | Performance |
|---|---|---|---|---|
| EUROIMMUN | 2 | 1.0 (1.0, 1.0) | <0.05 | Excellent |
| Platelia | 2 | 1.0 (1.0, 1.0) | <0.05 | Excellent |
| LIASON | 2 | 0.60 (0.35, 0.85) | 0.45 | Bad |
| LIASON | 3 | 0.60 (0.35, 0.85) | 0.45 | Bad |
| LIASON | 4 | 0.65 (0.40, 0.90) | 0.26 | Sufficient |
| COV2G | 2 | 0.59 (0.33, 0.85) | 0.50 | Bad |
| COV2G | 3 | 0.66 (0.40, 0.91) | 0.24 | Sufficient |
| COV2G | 4 | 0.66 (0.39, 0.92) | 0.24 | Sufficient |
| COV2T | 2 | 0.59 (0.33, 0.85) | 0.50 | Bad |
| COV2T | 3 | 0.55 (0.29, 0.81) | 0.71 | Bad |
| COV2T | 4 | 0.61 (0.35, 0.86) | 0.43 | Sufficient |
| Elecsys S | 2 | 0.95 (0.84, 1.0) | <0.05 | Excellent |
| Elecsys S | 3 | 1.0 (1.0, 1.0) | <0.05 | Excellent |
| Elecsys S | 4 | 1.0 (1.0, 1.0) | <0.05 | Excellent |
| Elecsys N | 2 | 1.0 (1.0, 1.0) | <0.05 | Excellent |
| Elecsys N | 3 | 1.0 (1.0, 1.0) | <0.05 | Excellent |
| Elecsys N | 4 | 1.0 (1.0, 1.0) | <0.05 | Excellent |
| VITROS | 2 | 0.93 (0.78, 1.0) | <0.05 | Excellent |
| VITROS | 3 | 0.93 (0.81, 1.0) | <0.05 | Excellent |
| VITROS | 4 | 0.96 (0.87, 1.0) | <0.05 | Excellent |
| Architect | 2 | 1.0 (1.0, 1.0) | <0.05 | Excellent |
| Architect | 3 | 1.0 (1.0, 1.0) | <0.05 | Excellent |
| Architect | 4 | 1.0 (1.0, 1.0) | <0.05 | Excellent |
| GSP/DELFIA | 2 | 1.0 (1.0, 1.0) | <0.05 | Excellent |
| In-house S (U of T) | 2 | 1.0 (1.0, 1.0) | <0.05 | Excellent |
| In-house RBD (U of T) | 2 | 1.0 (1.0, 1.0) | <0.05 | Excellent |
| In-house N (U of T) | 2 | 0.98 (0.93, 1.0) | <0.05 | Excellent |
| In-house S, polyclonal (U of O) | 2 | 1.0 (1.0, 1.0) | <0.05 | Excellent |
| In-house RBD, polyclonal (U of O) | 2 | 1.0 (1.0, 1.0) | <0.05 | Excellent |
| In-house N, polyclonal (U of O) | 2 | 1.0 (1.0, 1.0) | <0.05 | Excellent |
| In-house S, monoclonal (U of O) | 2 | 1.0 (1.0, 1.0) | <0.05 | Excellent |
| In-house RBD, monoclonal (U of O) | 2 | 1.0 (1.0, 1.0) | <0.05 | Excellent |
| In-house N, monoclonal (U of O) | 2 | 1.0 (1.0, 1.0) | <0.05 | Excellent |
DBS punches: 6 mm (1/4 inch) dried blood spot punch; 95% CI (LL, UL): 95% confidence intervals (lower limit, upper limit); S: Spike; RBD: Receptor binding domain; N: Nucleocapsid; U of T: University of Toronto; U of O: University of Ottawa.
aTest performance classified according to AUC as follows: <0.5 = not useful, 0.5–0.6 = bad, 0.6–0.7 = sufficient, 0.7–0.8 = good, 0.8–0.9 = very good, and 0.9–1.0 = excellent.
The panel consisted of 10 unique SARS-CoV-2 antibody positive DBS cards and 10 unique SARS-CoV-2 negative DBS cards contrived from patient samples.