TABLE 2.
Performance of DPP Syphilis Screen & Confirm with visual operator inspection and microreader analysis (cutoff of 9.0) according to HIV infection status
| Assay and detection method | No. of samples with: |
Agreement (95% CI) (%) | Sensitivity (95% CI) (%) | Specificity (95% CI) (%) | Kappa coefficient (95% CI) | |
|---|---|---|---|---|---|---|
| True-positive results | True-negative results | |||||
| HIV-1 positivea | ||||||
| Chembio treponemal componentb | n = 165 | n = 39 | ||||
| Operator reading | 138 | 39 | 86.7 (82.0–91.4) | 83.6 (77.1–88.9) | 100.0 (91.0–100.0) | 0.66 (0.55–0.77) |
| Microreader | 134 | 39 | 84.8 (79.8–89.7) | 81.2 (74.4–86.9) | 100.0 (91.9–100.0) | 0.62 (0.51–0.73) |
| Chembio nontreponemal componentb | n = 132 | n = 72 | ||||
| Operator reading | 100 | 63 | 79.9 (74.3–85.4) | 75.8 (67.5–82.8) | 87.5 (77.6–94.1) | 0.58 (0.47–0.69) |
| Microreader | 96 | 63 | 77.9 (72.2–83.6) | 72.7 (64.3–80.1) | 87.5 (77.6–94.1) | 0.55 (0.44–0.66) |
| HIV-1 negative | ||||||
| Chembio treponemal componentb | n = 139 | n = 40 | ||||
| Operator reading | 123 | 40 | 91.0 (86.8–95.2) | 88.5 (82.0–93.3) | 100.0 (91.2–100.0) | 0.77 (0.67–0.87) |
| Microreader | 119 | 40 | 88.8 (84.1–93.4) | 85.6 (78.7–91.0) | 100.0 (91.2–100.0) | 0.72 (0.61–0.83) |
| Chembio nontreponemal componentb | n = 110 | n = 69 | ||||
| Operator reading | 67 | 62 | 72.0 (65.4–78.7) | 60.9 (51.1–70.1) | 89.9 (80.2–95.8) | 0.46 (0.34–0.58) |
| Microreader | 63 | 63 | 70.3 (63.6–77.1) | 57.3 (47.5–66.7) | 91.3 (82.0–96.7) | 0.43 (0.32–0.55) |
a
The HIV-1 confirmatory test was Western blotting.
b
Reference tests were the TPPA test for treponemal antibodies and the RPR test for nontreponemal antibodies.