A cross-sectional study showing differences in the clinical diagnosis of pelvic inflammatory disease according to the experience of clinicians: implications for training and audit.

OBJECTIVES: Pelvic inflammatory disease (PID) generates diagnostic difficulty even for experienced doctors. Junior doctors and nurses also assess women with symptoms suggestive of PID. We aimed to determine if and how PID diagnoses vary between clinicians with different experience levels. METHODS: Cross-sectional study conducted in U.K. sexual health clinic, nested within a Chlamydia trachomatis (CT), and Neisseria gonorrhoea diagnostic test accuracy study. Proportions and characteristics of women diagnosed clinically with PID by clinicians with varying experience were compared. Outcomes included demographics, presenting symptoms and signs and CT, and CT and/or gonococcal (GC) (CT/GC) positivity. RESULTS: In 3804 women assessed by 36 clinicians, rates of PID, CT and GC were 4.4%, 10.5%, and 2.5%, with no differences between experienced and inexperienced clinicians (p=0.84, p=0.13 and p=0.07, respectively). 63.7% of PID diagnosed by experienced clinicians met Centers for Disease Control and Prevention (CDC) key clinical criteria versus 41.2% by inexperienced; experienced versus inexperienced OR 2.51; 95% CI 1.16 to 5.40). Proportions of CT (CT/GC)-positive PID increased with experience (5.9% (11.8%) to 31.9% (34.1%)); experienced versus inexperienced (OR 3.90; 95% CI 1.12 to 13.5). Percentages of women with CT (CT/GC) who were diagnosed with PID also rose with experience (2.2% (3.9%) to 14.2% (13.7%)), but CT prevalence in PID cases diagnosed by inexperienced clinicians (8.8%) was no greater than in all women they assessed (9.0%), suggesting poorer discriminative skills. CONCLUSIONS: Clinical diagnostic acumen for PID improves with experience. Inexperienced clinicians should focus on the presence of lower abdominal pain with pelvic tenderness and consider additional supportive symptoms, to improve specificity of their diagnoses. TRIAL REGISTRATION NUMBER: ISRCTN 42867448.

Assessment of best single sample for finding chlamydia in women with and without symptoms: a diagnostic test study.

OBJECTIVE: To compare vulvovaginal swabs with endocervical swabs as optimal diagnostic sample for detection of Chlamydia trachomatis infection. DESIGN: A diagnostic test study. SETTING: An urban sexual health centre. PARTICIPANTS: 3973 women aged ≥ 16 years requesting testing for sexually transmitted infections. INTERVENTIONS: Participants took a vulvovaginal swab before routine examination, and clinicians took an endocervical swab during examination. MAIN OUTCOME MEASURE: Diagnosis of chlamydia infection with samples analysed using the Aptima Combo-2 assay; positive results confirmed with the Aptima CT assay. RESULTS: Of the 3973 participants, 410 (10.3%) were infected with C trachomatis. Infected women were significantly younger (22 v 25 years, P<0.0001) and more likely to have symptoms suggestive of a bacterial sexually transmitted infection (53% v 41%, odds ratio 1.63 (95% CI 1.30 to 2.04)), be a contact of someone with a sexually transmitted infection (25% v 5%, odds ratio 6.18 (4.61 to 8.30)), clinically diagnosed with cervicitis (17% v 4%, odds ratio 4.92 (3.50 to 6.91)), and have pelvic inflammatory disease (9% v 3%, odds ratio 2.85 (1.87 to 4.33)). When women co-infected with gonorrhoea were included in the analysis, there was an association with mixed ethnicity (10% v 7%, odds ratio 1.53 (1.07 to 2.17)); but when those with gonorrhoea were removed, women of white ethnicity were significantly more likely to have chlamydia (85% v 80%, odds ratio 1.40 (1.03 to 1.91)). On analysis of complete paired results, vulvovaginal swabs were significantly more sensitive than endocervical swabs (97% (95% CI 95% to 98%) v 88% (85% to 91%), P<0.00001); corresponding specificities were 99.9% and 100%. In women with symptoms suggestive of a bacterial sexually transmitted infection, vulvovaginal swabs were significantly more sensitive than endocervical swabs (97% (93% to 98%) v 88% (83% to 92%), P=0.0008), as they were in women without symptoms (97% (94% to 99%) v 89% (84% to 93%), P=0.002). CONCLUSIONS: Vulvovaginal swabs are significantly better than endocervical swabs at detecting chlamydia in women with and without symptoms suggestive of sexually transmitted infections. In those with symptoms, using endocervical samples rather than vulvovaginal swabs would have missed 9% of infections, or 1 in every 11 cases of chlamydia. TRIAL REGISTRATION: ISRCTN42867448.

Assessment of self taken swabs versus clinician taken swab cultures for diagnosing gonorrhoea in women: single centre, diagnostic accuracy study.

OBJECTIVE: To compare gonorrhoea detection by self taken vulvovaginal swabs (tested with nucleic acid amplification tests) with the culture of urethral and endocervical samples taken by clinicians. DESIGN: Prospective study of diagnostic accuracy. SETTING: 1 sexual health clinic in an urban setting (Leeds Centre for Sexual Health, United Kingdom), between March 2009 and January 2010. PARTICIPANTS: Women aged 16 years or older, attending the clinic for sexually transmitted infection (STI) testing and consenting to perform a vulvovaginal swab themselves before routine examination. During examination, clinicians took urethral and endocervical samples for culture and an endocervical swab for nucleic acid amplification testing. INTERVENTIONS: Urethra and endocervix samples were analysed by gonococcal culture. Vulvovaginal swabs and endocervical swabs were analysed by the Aptima Combo 2 (AC2) assay; positive results from this assay were confirmed with a second nucleic acid amplification test. MAIN OUTCOME MEASURES: Positive confirmation of gonorrhoea. RESULTS: Of 3859 women with complete data and test results, 96 (2.5%) were infected with gonorrhoea (overall test sensitivities: culture 81%, endocervical swabs with AC2 96%, vulvovaginal swabs with AC2 99%). The AC2 assays were more sensitive than culture (P<0.001), but the endocervical and vulvovaginal assays did not differ significantly (P=0.375). Specificity of all Aptima Combo 2 tests was 100%. Of 1625 women who had symptoms suggestive of a bacterial STI, 56 (3.4%) had gonorrhoea (culture 84%, endocervical AC2 100%, vulvovaginal AC2 100%). The AC2 assays were more sensitive than culture (P=0.004), and the endocervical and vulvovaginal assays were equivalent to each other. Of 2234 women who did not have symptoms suggesting a bacterial STI, 40 (1.8%) had gonorrhoea (culture 78%, endocervical AC2 90%, vulvovaginal AC2 98%). The vulvovaginal swab was more sensitive than culture (P=0.008), but there was no difference between the endocervical and vulvovaginal AC2 assays (P=0.375) or between the endocervical AC2 assay and culture (P=0.125). The endocervical swab assay performed less well in women without symptoms of a bacterial STI than in those with symptoms (90% v 100%, P=0.028), whereas the vulvovaginal swab assay performed similarly (98% v 100%, P=0.42). CONCLUSION: Self taken vulvovaginal swabs analysed by nucleic acid amplification tests are significantly more sensitive at detecting gonorrhoea than culture of clinician taken urethral and endocervical samples, and are equivalent to endocervical swabs analysed by nucleic acid amplification tests. Self taken vulvovaginal swabs are the sample of choice in women without symptoms and have the advantage of being non-invasive. In women who need a clinical examination, either a clinician taken or self taken vulvovaginal swab is recommended.