Table 2.
Comparison of performance of the combined markers in the detection of confirmatory SARS-CoV-2 antibody among blood donors in Wuhan and other cities.
| Positive criterion | Screen out positive no. | True-positive no. (PPV, %) | True-positive missing no. (%) |
|---|---|---|---|
| Among TAb(+) Donors in Wuhan (n = 463) | |||
| TAb-R | 463 | 395 (85.31%) | 0 |
| TAb/IgM DR | 268 | 260(97.01%) | 135 (34.18%) |
| TAb/IgG-RBD DR | 388 | 383 (98.71%) | 12 (3.04%) |
| TAb/IgG-N DR | 313 | 309 (98.72%) | 86 (21.77%) |
| Among TAb(+) Donors in the other two cities (n = 81) | |||
| TAb-R | 81 | 3 (3.70 %) | 0 |
| TAb/IgM DR | 16 | 3 (18.75%) | 0 |
| TAb/IgG-RBD DR | 9 | 1 (11.11%) | 2 (66.67%) |
| TAb/IgG-N DR | 5 | 0 | 3 (100.00%) |
TAb total antibody against SARS-CoV-2, IgG-RBD IgG antibody against receptor-binding domain (RBD) of the spike protein of SARS-CoV-2, IgG-N IgG antibody against nucleoprotein of SARS-CoV-2, R reactive, DR reactive in double assays, PPV positive predictive value.