Table 3.
Performance of Assays Under Consideration for Detection of Pharyngeal and Rectal Neisseria gonorrhoeae and Chlamydia trachomatis
| Site and Infection | PPA (95% CI) | NPA (95% CI) | PPVa (95% CI) | NPVa (95% CI) | Positive LR (95% CI) | Negative LR (95% CI) |
|---|---|---|---|---|---|---|
| Pharynx, NG | ||||||
| Assay 1 | 94.7 (90.7–97.0) | 98.8 (98.2–99.1) | 87.1 (82.0–90.8) | 99.5 (99.2–99.7) | 77 (54–111) | 0.05 (.03–.10) |
| Assay 2 | 95.1 (91.3–97.3) | 98.8 (98.3–99.2) | 88.2 (83.3–91.8) | 99.6 (99.2–99.8) | 78 (54–112) | 0.05 (.03–.09) |
| Assay 3 | 84.8 (79.4–89.0) | 99.5 (99.2–99.7) | 94.2 (89.9–96.7) | 98.7 (98.1–99.0) | 183 (101–330) | 0.15 (.11–.21) |
| Rectum, NG | ||||||
| Assay 1 | 91.2 (86.5–94.4) | 99.6 (99.3–99.8) | 95.4 (91.5–97.6) | 99.3 (98.8–99.5) | 238 (124–457) | 0.08 (.05–.15) |
| Assay 2 | 96.5 (92.9–98.3) | 99.2 (98.8–99.5) | 92.8 (88.4–95.6) | 99.8 (99.5–99.9) | 127 (80–202) | 0.04 (.02–.07) |
| Assay 3 | 88.3 (83.2–92.0) | 99.6 (99.2–99.8) | 94.8 (90.6–97.1) | 99.0 (98.5–99.3) | 205 (110–381) | 0.12 (.08–.17) |
| Pharynx, CT | ||||||
| Assay 1 | 95.9 (86.3–98.9) | 99.7 (99.4–99.8) | 85.5 (73.8–92.4) | 99.9 (99.7–100.0) | 303 (151–606) | 0.04 (.01–.16) |
| Assay 2 | 88.2 (76.6–94.5) | 99.7 (99.4–99.8) | 84.9 (72.9–92.1) | 99.8 (99.5–99.9) | 279 (139–562) | 0.12 (.06–.25) |
| Assay 3 | 84.0 (71.5–91.7) | 99.8 (99.5–99.9) | 89.4 (77.4–95.4) | 99.7 (99.4–99.8) | 354 (158–794) | 0.16 (.08–.30) |
| Rectum, CT | ||||||
| Assay 1 | 86.0 (80.9–89.9) | 99.3 (98.9–99.6) | 92.5 (88.1–95.3) | 98.6 (98.1–99.0) | 124 (76–203) | 0.14 (.10–.19) |
| Assay 2 | 88.7 (83.9–92.3) | 98.7 (98.2–99.1) | 88.7 (83.9–92.3) | 99.1 (98.7–99.4) | 70 (49–100) | 0.11 (.08–.17) |
| Assay 3 | 83.0 (77.5–87.2) | 99.1 (98.6–99.4) | 90.0 (85.3–93.4) | 98.3 (97.7–98.8) | 91 (59–140) | 0.17 (.13–.23) |
Abbreviations: CI, confidence interval; CT, Chlamydia trachomatis; LR, likelihood ratio; NG, Neisseria gonorrhoeae; NPA, negative percent agreement; NPV, negative predictive value; PPA, positive percent agreement; PPV, positive predictive value.
aPPVs and NPVs were calculated based on the positivity observed in this study.