Table 3.
Sensitivities, specificities, and positive and negative predictive values of testing for Chlamydia trachomatis infection with self taken vulvovaginal swabs or with clinician taken endocervical swabs as diagnostic samples among 3867 women recruited at a sexual health centre. Values are percentages
| Sensitivity (95% CI) | Specificity (95% CI) | Predictive value | ||
|---|---|---|---|---|
| Positive | Negative | |||
| Whole cohort | ||||
| Endocervical swab | 88 (85 to 91) | 100 (99.9 to 100) | 100 | 98.7 |
| Vulvovaginal swab | 97 (95 to 98) | 99.9 (99.8 to 100) | 99.5 | 99.7 |
| Women with symptoms suggestive of bacterial sexually transmitted infection | ||||
| Endocervical swab | 88 (83 to 92) | 100 (99.7 to 100) | 100 | 98.2 |
| Vulvovaginal swab | 97 (93 to 98) | 99.9 (99.6 to 100) | 99.5 | 99.5 |
| Women without symptoms suggestive of bacterial sexually transmitted infection | ||||
| Endocervical swab | 89 (84 to 93) | 100 (99.8 to 100) | 100 | 99.0 |
| Vulvovaginal swab | 97 (94 to 99) | 99.9 (99.7 to 100) | 99.4 | 99.8 |
| Women suitable for asymptomatic screen | ||||
| Endocervical swab | 89 (81 to 95) | 100 (99.7 to 100) | 100 | 99.4 |
| Vulvovaginal swab | 95 (87 to 98) | 99.9 (99.6 to 100) | 98.6 | 99.7 |