Table 3. Table comparing the results of Chagas Stat Pack (CSP) and Chagas Detect Plus (CDP) individually or taking into consideration their combined use (RDTs) versus the "gold-standard" based on ELISAs.
| ELISAs* | CSP | CDP | RDTs# | |
|---|---|---|---|---|
| False positive | 0 | 10 | 49 | 15 |
| True positive | 304 | 297 | 299 | 297 |
| False negative | 0 | 7 | 5 | 7 |
| True negative | 381 | 371 | 332 | 366 |
| Total | 685 | 685 | 685 | 685 |
| % Agreement | - | 97.5 | 92.1 | 96.8 |
| Kappa (CI95%) | - | 0.95 (0.93–0.97) | 0.84 (0.80–0.88) | 0.94 (0.91–0.96) |
| Sensitivity | - | 97.7 | 98.4 | 97.7 |
| Specificity | - | 97.4 | 87.1 | 96.1 |
| PPV | - | 96.7 | 85.9 | 95.2 |
| NPV | - | 98.1 | 98.5 | 98.1 |
| DE | - | 97.5 | 92.1 | 96.8 |
Note that CSP, CDP and RDTs results of “% of agreement” (and kappa value), “sensitivity”, “specificity”, “PPV”, “NPV” and “DE” shown in the table correspond to their comparison to the outcome of using the ELISAs.
*, results obtained with the standard algorithm based on the agreement of two conventional serological tests (ELISAs in this case);
#, results obtained with the combined use of up to three RDTs, as described.