TABLE 3.
Clinical performance comparison of four EUA molecular assays for the detection of SARS-CoV-2 in nasopharyngeal swab specimens (n = 104)
| Molecular assay and result |
No. of results by reference standarda |
Kappa (κ) (± 95% CI)b,c | PPA (± 95% CI)c | NPA (± 95% CI)c | |
|---|---|---|---|---|---|
| Positive | Negative | ||||
| Modified CDC | |||||
| Positive | 51 | 1d | 0.98 (0.94–1) | 100 (0.93–1) | 98 (0.89–0.99) |
| Negative | 0 | 52 | |||
| DiaSorin Molecular | |||||
| Positive | 51 | 0 | 1.0 (0.99–1) | 100 (0.93–1) | 100 (0.93–1) |
| Negative | 0 | 53 | |||
| GenMark | |||||
| Positive | 49 | 0 | 0.96 (0.91–1) | 96 (0.87–0.99) | 100 (0.93–1) |
| Negative | 2e | 53 | |||
| Hologic | |||||
| Positive | 51 | 2f | 0.96 (0.91–1) | 100 (0.93–1) | 96 (0.87–0.99) |
| Negative | 0 | 51 | |||
a
The reference standard was defined as the result obtained from at least 3 of the 4 molecular assays.
b
Kappa values representing levels of agreement are categorized as follows: >0.90, almost perfect; 0.80 to 0.90, strong; 0.60 to 0.79, moderate; 0.40 to 0.59, weak; 0.21 to 0.39, minimal; (0 to 0.20), none.
c
± 95% CI, upper/lower 95% confidence interval.
d
This one sample had cycle threshold (CT) values of 38.9 and 39.6 for N1 and N2, respectively, by the CDC assay.
e
Cycle threshold (CT) value undetermined.
f
These two samples had cycle threshold (CT) values of 36.2 and 38.5 by the Hologic assay.