TABLE 4.
Comparison of the sensitivities and specificities of three commercially available diagnostic tests for scrub typhusa
| Parameter | Company B |
Company C |
Company D |
|||||||
|---|---|---|---|---|---|---|---|---|---|---|
| IgM |
IgG |
IgM |
IgG |
Total Ig |
||||||
| Case | Control | Case | Control | Case | Control | Case | Control | Case | Control | |
| No. of test results: | ||||||||||
| Positive | 45 | 2 | 47 | 10 | 52 | 1 | 35 | 0 | 71 | 21 |
| Negative | 25 | 37 | 23 | 29 | 45 | 197 | 62 | 198 | 26 | 179 |
| Total | 70 | 39 | 70 | 39 | 97 | 198 | 97 | 198 | 97 | 200 |
| Sensitivity, % (95% CI) | 64.3 (51.9–75.1) | 67.1 (54.8–77.6) | 53.6 (43.2–63.7) | 36.1 (26.8–46.5) | 73.2 (63.1–81.4) | |||||
| Specificity, % (95% CI) | 94.9 (81.4–99.1) | 74.4 (57.6–86.4) | 99.5 (96.8–100.0) | 100.0 (97.6–100.0) | 89.5 (84.2–93.2) | |||||
| PPV, % (95% CI) | 95.7 (84.3–99.3) | 82.5 (69.6–90.8) | 98.1 (88.6–99.9) | 100.0 (87.7–100.0) | 77.2 (67.0–85.0) | |||||
| NPV, % (95% CI) | 59.7 (46.5–71.7) | 55.8 (41.4–69.3) | 81.4 (75.8–86.0) | 76.2 (70.4–81.1) | 87.3 (81.8–91.4) | |||||
a
95% CI, 95% confidence interval; Ig, immunoglobulin; PPV, positive predictive value; NPV, negative predictive value.