Table 2.
Performance estimates of syndromic diagnosis algorithms for women with STIs
| Women with STIs * [n (%)] N = 98 | Sensitivity (95% CI) | Specificity (95% CI) | PPV (95% CI) | NPV (95% CI) | |
|---|---|---|---|---|---|
| Symptom | |||||
| Complaint of vaginal discharge | 5 (6.8) | 6.8 (2.5–15.9) | 93.9 (90.0–96.4) | 25.0 (9.6–49.4) | 77.3 (72.1–81.9) |
| Complaint of vulvitis | 4 (4.1) | 4.1 (1.3–10.8) | 98.3 (96.1–99.3) | 40.0 (13.7–72.6) | 78.4 (74.2–82.2) |
| Clinical sign | |||||
| Abnormal vaginal discharge on exam | 56 (57.7) | 57.7 (47.3–67.6) | 51.5 (46.0–56.8) | 25.1 (19.7–31.4) | 81.2 (75.2–86.0) |
| Cervical ulcer seen on exam | 4 (4.1) | 4.1 (1.3–10.8) | 99.1 (97.3–99.8) | 57.1 (20.3–88.2) | 78.6 (74.3–82.3) |
| Risk factor | |||||
| Age < 21 | 21 (21.4) | 21.4 (14.0–31.1) | 88.9 (85.1–91.9) | 35.0 (23.4–48.5) | 80.3 (75.9–84.0) |
| History of STIs in lifetime | 20 (20.4) | 20.4 (13.2–30.0) | 87.5 (83.5–90.7) | 31.3 (20.6–44.2) | 79.8 (75.4–83.6) |
| Primary education only | 67 (69.8) | 69.8 (59.4–78.5) | 42.8 (37.5–48.2) | 25.3 (20.3–31.0) | 83.6 (77.1–88.6) |
| Syndromic algorithm | |||||
| All three above risk factors | 7 (7.1) | 7.1 (3.2–14.7) | 99.4 (97.7–99.9) | 77.8 (40.2–96.1) | 79.4 (75.2–83.0) |
| Any one of above three risk factors | 73 (74.5) | 74.5 (64.5–82.5) | 35.5 (30.6–40.8) | 24.3 (19.7–29.7) | 83.3 (76.2–88.7) |
| Complaint of vaginal discharge + any one of above risk factors | 4 (4.1) | 4.1 (1.3–10.7) | 97.7 (95.4–98.9) | 33.3 (11.3–64.6) | 78.5 (74.3–82.2) |
| Abnormal vaginal discharge on exam + any one of above risk factors | 44 (44.9) | 44.9 (34.9–55.3) | 69.9 (64.8–74.6) | 29.3 (22.3–37.4) | 82.0 (77.1–86.1) |
STI = sexually transmitted infections; CI = confidence interval; NPV = negative predictive value; PPV = positive predictive value
*
STIs (sexually transmitted infections) is defined as one or more of trichomoniasis, gonorrhoea, chlamydia or syphilis on diagnostic testing