TABLE 1: Performance of Ag-RDT using nasopharyngeal, nasal, and saliva samples compared to RT-qPCR for COVID-19 suspected participants.
| Results | Test Performance, % (95% CI) | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Parameter | TP | TN | FP | FN | Sensitivity | Specificity | PPV | NPV | Accuracy | Kappa Index | Kappa Agreement |
| Overall | 177 | 303 | 7 | 120 | 60 (54-65) | 98 (95-99) | 96 (92-98) | 72 (69-74) | 79 (76-82) | 0.58 | Moderate |
| Age | |||||||||||
| 1-30 yrs | 5 | 58 | 1 | 4 | 56 (21-86) | 98 (91-100) | 83 (40-97) | 94 (88-97) | 93 (84-98) | 0.63 | Substantial |
| 31-60 yrs | 88 | 120 | 2 | 62 | 59 (50-67) | 98 (94-100) | 98 (92-99) | 66 (62-70) | 77 (71-81) | 0.55 | Moderate |
| 61-80 yrs | 64 | 98 | 3 | 44 | 59 (49-69) | 97 (92-99) | 96 (87-99) | 69 (64-74) | 78 (71-83) | 0.56 | Moderate |
| >81 yrs | 20 | 27 | 1 | 10 | 67 (47-83) | 96 (82-100) | 95 (74-99) | 73 (62-82) | 81 (69-90) | 0.62 | Substantial |
| Number of days with symptoms | |||||||||||
| <3 | 9 | 37 | 0 | 8 | 53 (28-77) | 100 (91-100) | 100 | 82 (74-89) | 85 (73-93) | 0.61 | Substantial |
| 4-7 | 112 | 213 | 5 | 68 | 62 (55-69) | 98 (95-99) | 96 (90-98) | 76 (72-79) | 82 (78-85) | 0.62 | Substantial |
| 8-10 | 54 | 46 | 2 | 42 | 58 (45-70) | 94 (79-99) | 95 (83-99) | 52 (44-59) | 70 (59-79) | 0.43 | Moderate |
| >11 | 2 | 7 | 0 | 2 | 53 (36-70) | 100 (86-100) | 100 | 59 (50-67) | 72 (59-83) | 0.47 | Moderate |
| Type of sample | |||||||||||
| Nasopharyngeal | 124 | 223 | 4 | 77 | 62 (5-68) | 98 (96-100) | 97 (96-100) | 74 (71-78) | 81 (77-85) | 0.61 | Substantial |
| Nasal | 29 | 46 | 2 | 28 | 51 (37-64) | 96 (86-100) | 94 (79-98) | 62 (56-68) | 71 (62-80) | 0.45 | Moderate |
| Saliva | 24 | 34 | 1 | 15 | 66 (45-77) | 97 (85-100) | 96 (77-99) | 69 (60-77) | 78 (67-87) | 0.58 | Moderate |
TP: true positive; TN: true negative; FP: false positive; FN: false negative; CI: confidence interval; PPV: positive predictive value; NPV: negative predictive value.