Table II.
Diagnostic characteristics of rapid diagnostic test with reference to rRT-PCR: Overall and subgroup analysis
| Diagnostic characteristics | Overall | Subgroups | ||
|---|---|---|---|---|
| Duration of illness ≤5 days (n=191) | Duration of illness >5 days (n=12) | Asymptomatic (n=127) | ||
| TP | 63 | 49 | 5 | 9 |
| TN | 252 | 134 | 5 | 113 |
| FP | 1 | 0 | 0 | 1 |
| FN | 14 | 8 | 2 | 4 |
| Ct values (mean±SD) (minimum-maximum) | 21.4±5.0 (10-35.4) | 21.1±4.8 (10-35.4) | 25.1±4.8 (15.1-30.4) | 20.7±5.0 (16.9-34.1) |
| Sensitivity % (95% CI) | 81.8 (71.3-89.6) | 85.9 (74.2-93.7) | 71.4 (29.0-96.3) | 69.2 (38.5-90.9) |
| Specificity % (95% CI) | 99.6 (97.8-99.9) | 100 (97.2-100) | 100 (47.8-100) | 99.1 (95.2-99.9) |
| PPV % (95% CI) | 98.4 (88.8-99.7) | 100 | 100 | 90.0 (55.2-98.4) |
| NPV % (95% CI) | 94.7 (91.8-96.6) | 94.3 (89.7-96.9) | 71.4 (43.6-89.0) | 96.0 (92.5-98.4) |
| Accuracy % (95% CI) | 95.4 (92.6-97.4) | 95.8 (91.8-98.2) | 83.3 (51.6-97.9) | 96.0 (91.0-98.7) |
| LR+ (95% CI) | 207.0 (29.1-1468.0) | CNC | CNC | 78.9 (10.5-574.3) |
| LR− (95% CI) | 0.18 (0.11-0.29) | 0.14 (0.07-0.27) | 0.28 (0.08-0.92) | 0.31 (0.14-0.70) |
CI, confidence interval; Ct, cycle threshold; PPV, positive predictive value; NPP, negative predictive value; LR, likelihood ratio; CNC, could not be calculated (due to zero FP RDT result); RDT, rapid diagnostic test; TP, true positive; TN, true negative; FP, false positive; FN, false negative