Table 5.
Clinical performance of the STI-MS assay for organism identification compared to that of monoplex real-time PCR
| Target organism | Sample types | No. of samples with the following result | Sensitivity (%) (95% CI) | Specificity (%) (95% CI) | PPV (%) (95% CI) c | NPV (%) (95% CI) c | ||||
|---|---|---|---|---|---|---|---|---|---|---|
| TP | FP | FN | TN | Total | ||||||
| Herpes simplex virus types 1 | Urine | 1 | 0 | 0 | 116 | 117 | 100 (5.5–100) | 100 (96.0–100) | 100 (5.5–100) | 100 (96.0–100) |
| Swabs a | 1 | 1 | 0 | 122 | 124 | 100 (5.5–100) | 99.2 (94.9–100) | 50 (2.7–97.3) | 100 (96.2–100) | |
| Herpes simplex virus types 2 | Urine | 1 | 1 | 0 | 115 | 117 | 100 (5.5–100) | 99.2 (94.6–100) | 50 (2.7–97.3) | 100 (96.0–100) |
| Swabs a | 1 | 1 | 0 | 122 | 124 | 100 (5.5–100) | 99.2 (94.9–100) | 50 (2.7–97.3) | 100 (96.2–100) | |
| Chlamydia trachomatis | Urine | 3 | 0 | 0 | 114 | 117 | 100 (3.1–100) | 100 (96.0–100) | 100 (31.0–100) | 100 (96.0–100) |
| Swabs a | 12 | 2 | 0 | 110 | 124 | 100 (69.9–100) | 98.2 (93.1–99.7) | 85.7 (56.2–97.5) | 100 (95.8–100) | |
| Treponema pallidum | Urine | 0 | 0 | 1 | 116 | 117 | 0 (0–94.5) | 100 (96.0–100) | NA | 99.1 (94.6–100) |
| Swabs a | 0 | 0 | 1 | 123 | 124 | 0 (0–94.5) | 100 (96.2–100) | NA | 99.2 (95.0–100) | |
| Neisseria gonorrhoeae | Urine | 6 | 3 | 1 | 107 | 117 | 85.7 (42.0–99.3) | 97.3 (91.6–99.3) | 66.7 (31.0–91.0) | 99.1 (94.2–100) |
| Swabs a | 2 | 1 | 0 | 121 | 124 | 100 (19.8–100) | 99.2 (94.8–100) | 66.7 (12.5–98.2) | 100 (96.2–100) | |
| Trichomonas vaginalis | Urine | 0 | 0 | 0 | 117 | 117 | NA | 100 (96.0–100) | NA | 100 (96.0–100) |
| Swabs a | 1 | 0 | 0 | 123 | 124 | 100 (5.5–100) | 100 (96.2–100) | 100 (5.5–100) | 100 (96.2–100) | |
| Mycoplasma hominis | Urine | 5 | 0 | 0 | 112 | 117 | 100 (46.3–100) | 100 (95.9–100) | 100 (46.3–100) | 100 (95.9–100) |
| Swabs a | 14 | 2 | 0 | 108 | 124 | 100 (73.2–100) | 98.2 (93.0–99.7) | 87.5 (60.4–97.8) | 100 (95.7–100) | |
| Ureaplasma urealyticum | Urine | 8 | 6 | 0 | 103 | 117 | 100 (59.8–100) | 94.5 (87.9–97.7) | 57.1 (29.6–81.2) | 100 (95.5–100) |
| Swabs a | 11 | 6 | 0 | 107 | 124 | 100 (67.9–100) | 94.7 (88.3–97.8) | 64.7 (38.6–84.7) | 100 (95.7–100) | |
| Mycoplasma genitalium | Urine | 2 | 2 | 0 | 113 | 117 | 100 (19.8–100) | 98.3 (93.2–99.7) | 50 (9.2–90.8) | 100 (96.0–100) |
| Swabs a | 2 | 0 | 0 | 122 | 124 | 100 (19.8–100) | 100 (96.2–100) | 100 (19.8–100) | 100 (96.2–100) | |
| Ureaplasma parvum | Urine | 2 | 1 | 0 | 114 | 117 | 100 (19.8–100) | 99.1 (94.5–100) | 66.7 (12.5–98.2) | 100 (96.0–100) |
| Swabs a | 46 | 6 | 0 | 72 | 124 | 100 (90.4–100) | 92.3 (83.4–96.8) | 88.5 (75.9–95.2) | 100 (93.7–100) | |
| Haemophilus ducreyi | Urine | 0 | 0 | 0 | 117 | 117 | NA | 100 (96.0–100) | NA | 100 (96.0–100) |
| Swabs a | 0 | 0 | 0 | 124 | 124 | NA | 100 (96.3–100) | NA | 100 (96.3–100) | |
Note: aUrethral/cervical swab.
Abbreviations: TP, true positive; FP, false positive; FN, false negative; TN, true negative; CI, confidence interval; PPV, positive predictive value; NPV, negative predictive value; NA, not available.