Table 2. Operating characteristics of molecular tests in acute and chronic phases including all negative patients (with and without risk factors).
| Operating characteristics | Acute phase N = (71/86) | Chronic phase N = (481/622) | ||
|---|---|---|---|---|
| qPCR (95% CI) | cPCR (95% CI) | qPCR (95% CI) | cPCR (95% CI) | |
| Sensitivity | 95.7 (88.3–98.5) | 84.5 (74.3–91.2) | 64.2 (59.8–68.4) | 56.8 (52.3–61.1) |
| Specificity | 100.0 (79.6–100.0) | 100.0(79.6–100.0) | 97.1 (92.9–98.8) | 97.9 (93.9–99.2) |
| PPV | 100.0 (94.6–100.0) | 100.0 (93.9–100.0) | 98.7 (96.7–99.5) | 98.9(96.8–99.6) |
| NPV | 83.3 (60.8–94.2) | 57.69 (38.9–74.5) | 44.3 (38.9–49.9) | 39.8 (34.9–45.1) |
| DP | 96.5 (90.2–98.8) | 87.2 (78.5–92.8) | 71.7 (68.0–75.1) | 66.0 (62.3–69.6) |
| LR+ | Undefined | 22.6 (13.82–37.09) | 26.68 (13.8–51.5) | |
| LR- | 0.04 (0.02–0.1) | 0.15 (0.13–0.18) | 0.37 (0.36–0.37) | 0.44 (0.43–0.45) |
| Kappa index | 0.89 (0.7–1.1) | 0.62 (0.5–0.9) | 0.43 (0.36–0.49) | 0.36 (0.29–0.42) |
| AUC | 0.98 (0.91–0.99) | 0.92 (0.88–0.96) | 0.81 (0.77–0.84) | 0.77 (0.74–0.81) |
PPV: Positive predictive value; NPV: Negative predictive value; DP: diagnostic precision; LR+: positive likelihood ratio; LR-: negative likelihood ratio. N = (Positive gold standard/ total assayed). When the specificity is 100% the positive likelihood ratio is undefined.