Table 3.
Sensitivity (%), specificity (%), positive and negative predictive values (%), and accuracy (%) and their respective 95% confidence intervals resulting from the use of serological techniques (ELISA + Western blot, ELISA/WB), real-time PCR (qPCR) and both techniques to identify chronic and acute cases of dogs and owners infected with Trypanosoma cruzi in a rural community from southern Mexico
| Serological techniques (ELISA/WB) | qPCR | Combined | |
|---|---|---|---|
| Dogs | |||
| Sensitivity (%) | 67.6 (51.9–83.4) | 76.5 (62.2–90.7) | 92.4 |
| Specificity (%) | 100 | 100 | 100 |
| False positive (%) | 0 | 0 | – |
| False negative (%) | 32.4 (19.1–49.2) | 23.5 (12.4–40.0) | – |
| Predictive value (positive) (%) | 100 | 100 | 100 |
| Predictive value (negative) (%) | 83.3 (74.3–92.3) | 87.3 (79.1–95.5) | 95.5 |
| True prevalence (%) | 38.2 (28.1–48.3) | 38.2 (28.1–48.3) | – |
| Apparent prevalence (%) | 25.8 (16.7–34.9) | 29.2 (19.8–38.7) | – |
| Accuracy (%) | 87.6 (80.8–94.5) | 91.0 (85.1–97.0) | 96.6 |
| Humans | |||
| Sensitivity (%) | 63.6 (35.2–92.1) | 81.8 (59.0–100) | 93.4 |
| Specificity (%) | 100 | 100 | 100 |
| False positive (%) | 0 | 0 | – |
| False negative (%) | 36.4 (15.2–64.6) | 18.2 (5.1–47.7) | – |
| Predictive value (positive) (%) | 100 | 100 | 100 |
| Predictive value (negative) (%) | 95.1 (90.5–99.8) | 97.5 (94.1–100) | 99.1 |
| True prevalence (%) | 12.4 (5.5–19.2) | 12.4 (5.5–19.2) | – |
| Apparent prevalence (%) | 7.9 (2.3–13.5) | 10.1 (3.8–16.4) | – |
| Accuracy (%) | 95.5 (91.2–99.8) | 97.8 (94.7–100) | 98.9 |