Syndromic diagnosis and laboratory-confirmed STIs
| Syndromic diagnosis | Any STI, n (%)* | Chlamydia trachomatis, n (%)* | Neisseria gonorrhoeae, n (%)* | Trichomonas vaginalis, n (%)* | |||||||||
| Yes | No | Performance (95% CI) | Yes | No | Performance (95% CI) | Yes | No | Performance (95% CI) | Yes | No | Performance (95% CI) | ||
| Antenatal clinics (n=765) | |||||||||||||
| LAPS (166/765; 21.7%) | Yes | 60 (18.4) | 106 (14.2) | Sens: 18% (14% to 23%) Spec: 76% (72% to 80%) PPV: 36% (29% to 44%) NPV: 55% (51% to 59%) | 30 (17.1) | 136 (23.0) | Sens: 17% (12% to 24%) Spec: 77% (73% to 80%) PPV: 18% (13% to 25%) NPV: 76% (72% to 79%) | 15 (13.8) | 151 (23.0) | Sens: 14% (8% to 22%) Spec: 77% (74% to 80%) PPV: 9% (5% to 14%) NPV: 84% (81% to 87%) | 29 (83.0) | 457 (77.0) | Sens: 17% (12% to 23%) Spec: 77% (73% to 80%) PPV: 17% (12% to 24%) NPV: 76% (73% to 80%) |
| No | 267 (81.7) | 332 (75.8) | 145 (82.9) | 454 (77.0) | 94 (86.2) | 505 (77.0) | 142 (83.0) | 457 (77.0) | |||||
| VDS (156/765; 20.4%) | Yes | 60 (18.4) | 96 (22.0) | Sens: 18% (14% to 23%) Spec: 78% (74% to 82%) PPV: 38% (40% to 47%) NPV: 56% (52% to 60%) | 37 (21.1) | 119 (20.2) | Sens: 21% (15% to 28%) Spec: 80% (76% to 83%) PPV: 24% (17% to 31%) NPV: 77% (74% to 81%) | 16 (14.7) | 140 (21.3) | Sens: 15% (9% to 23%) Spec: 79% (75% to 82%) PPV: 10% (96% to 16%) NPV: 85% (82% to 87%) | 33 (19.3) | 123 (20.7) | Sens: 19% (14% to 26%) Spec: 79% (76% to 82%) PPV: 21% (15% to 28%) NPV: 77% (74% to 81%) |
| No | 267 (81.7) | 342 (78.1) | 138 (78.9) | 471 (79.8) | 93 (85.3) | 516 (78.7) | 138 (80.7) | 471 (79.3) | |||||
| Well woman clinics (n=614) | |||||||||||||
| LAPS (200/614; 32.6%) | Yes | 46 (29.9) | 154 (33.5) | Sens: 30% (23% to 38%) Spec: 67% (62% to 71%) PPV: 23% (17% to 29%) NPV: 74% (69% to 78%) | 19 (41.3) | 181 (31.9) | Sens: 41% (27% to 57%) Spec: 68% (64% to 72%) PPV: 10% (6% to 14%) NPV: 93% (91% to 96%) | 15 (30.6) | 185 (32.7) | Sens: 31% (18% to 45%) Spec: 67% (63% to 71%) PPV: 8% (4% to 12%) NPV: 92% (89% to 94%) | 24 (26.1) | 176 (33.7) | Sens: 26% (17% to 36%) Spec: 66% (62% to 70%) PPV: 12% (8% to 17%) NPV: 84% (80% to 87%) |
| No | 108 (70.1) | 306 (66.5) | 27 (58.8) | 387 (68.1) | 34 (69.4) | 380 (67.3) | 68 (73.9) | 346 (66.3) | |||||
| VDS (422/614; 68.7%) | Yes | 114 (74.0) | 308 (67.0) | Sens: 74% (66% to 81%) Spec: 33% (29% to 38%) PPV: 25% (22% to 29%) NPV: 79% (74% to 84%) | 33 (71.7) | 389 (68.5) | Sens: 72% (57% to 84%) Spec: 32% (28% to 36%) PPV: 8% (6% to 9%) NPV: 93% (90% to 96%) | 37 (75.5) | 385 (68.1) | Sens: 75% (61% to 87%) Spec: 32% (28% to 36%) PPV: 9% (7% to 10%) NPV: 94% (90% to 96%) | 70 (76.1) | 352 (67.4) | Sens: 76% (66% to 84%) Spec: 33% (28% to 37%) PPV: 17% (15% to 18%) NPV: 89% (84% to 92%) |
| No | 40 (26.0) | 152 (33.0) | 13 (28.3) | 179 (31.5) | 12 (24.5) | 180 (31.9) | 22 (23.9) | 170 (32.6) | |||||
| Sexual health clinics (n=385) | |||||||||||||
| LAPS (282/385; 73.2%) | Yes | 109 (75.1) | 173 (72.1) | Sens: 75% (67% to 82%) Spec: 28% (22% to 34%) PPV: 39% (33% to 45%) NPV: 65% (55% to 74%) | 62 (79.5) | 220 (71.7) | Sens: 79% (69% to 88%) Spec: 28% (23% to 34%) PPV: 22% (20% to 24%) NPV: 84% (77% to 90%) | 46 (27.0) | 236 (73.3) | Sens: 73% (60% to 83%) Spec: 27% (22% to 32%) PPV: 16% (12% to 21%) NPV: 84% (75% to 90%) | 40 (74.1) | 242 (73.1) | Sens: 74% (60% to 85%) Spec: 27% (22% to 32%) PPV: 14% (11% to 18%) NPV: 86% (78% to 92%) |
| No | 36 (24.8) | 67 (27.9) | 16 (20.5) | 87 (28.3) | 17 (27.0) | 86 (26.7) | 14 (25.9) | 89 (26.9) | |||||
| VDS (281/385; 73.0%) | Yes | 106 (73.1) | 175 (72.9) | Sens: 73% (65% to 80%) Spec: 27% (22% to 33%) PPV: 38% (35% to 41%) NPV: 62% (54% to 70%) | 61 (78.2) | 220 (71.7) | Sens: 78% (67% to 87%) Spec: 28% (23% to 34%) PPV: 22% (19% to 24%) NPV: 84% (76% to 89%) | 42 (66.7) | 239 (74.2) | Sens: 67% (54% to 78%) Spec: 26% (21% to 31%) PPV: 15% (13% to 17%) NPV: 80% (73% to 85%) | 40 (74.1) | 241 (72.8) | Sens: 74% (60% to 85%) Spec: 27% (22% to 32%) PPV: 14% (12% to 16%) NPV: 86% (80% to 91%) |
| No | 39 (26.9) | 65 (27.1) | 17 (21.8) | 87 (28.3) | 21 (33.3) | 83 (25.8) | 14 (25.9) | 90 (27.2) | |||||
*Prevalence of any and individual STIs in this population.
LAPS, lower abdominal pain syndrome; NPV, negative predictive value; PPV, positive predictive value; Sens, sensitivity; Spec, specificity; STI, sexually transmitted infection; VDS, vaginal discharge syndrome.