Table 4. Diagnostic performance of ddPCR and RT-PCR for suspect outpatients.
| Clinically positive | Clinically negative | Sensitivity (95% CI) |
Specificity (95% CI) |
PPV (95% CI) |
NPV (95% CI) |
Negative likelihood ratio (95% CI) | Accuracy (95% CI) |
||
|---|---|---|---|---|---|---|---|---|---|
| RT-PCR | Test positive | 21 a | 0b | 40% (27–55%) |
100% (54–100%) |
100% (NA) |
16% (13–19%) |
0.60 (0.48–0.75) |
47% (33–60%) |
| Test negative | 31 c | 6d | |||||||
| ddPCR | Test positive | 47 a | 0b | 94% (83–99%) |
100% (48–100%) |
100% (NA) |
63% (36–83%) |
0.06 (0.02–0.18) |
95% (84–99%) |
| Test negative | 3 c | 5d | |||||||
| Suspect | 2 | 1 |
Note: Sensitivity = [a/(a + c)] × 100%; Specificity = [d/(b + d)] × 100%; PPV = [a/(a + b)] × 100%, positive predictive value;
NPV = [d / (c + d)] × 100%, negative predictive value; Negative likelihood ratio = (1-Sensitivity)/Specificity;
Accuracy = [(a + d) / (a + b + c + d)] × 100%; NA, not applicable.
Calculated by MEDCALC (https://www.medcalc.org/calc/diagnostic_test.php).