Clinical performance and acceptability of self-collected vaginal and urine samples compared with clinician-taken cervical samples for HPV testing among women referred for colposcopy. A cross-sectional study

Abstract

ObjectivesTo increase effectiveness of the cervical cancer screening program, self-sampling can be an option. Both self-collected vaginal samples (SCV) and urine samples may be useful alternatives to clinician-taken cervical samples (CS).DesignCross-sectional study.SettingColposcopy clinic.ParticipantsWomen (n=305) referred to colposcopy after abnormal cervical screening result or conditions like postcoital bleeding.InterventionAll women self-collected a urine and a vaginal sample prior to colposcopy, where a CS and biopsies were taken. All samples were tested for high-risk human papillomavirus (HPV) using the Cobas HPV assay. The gold standard was histology diagnoses (CIN2+/CIN3+) from biopsies obtained at the same examination.Primary outcomeAbsolute and relative sensitivity and specificity of HPV testing on SCV and urine to detect CIN2+/CIN3+ compared with the CS.Secondary outcomeThe acceptability by women of self-sampling.ResultsBoth the vaginal and urine sample were comparable to the CS in identifying severe intraepithelial neoplasia (CIN2+/CIN3+). Absolute sensitivity ranged from 93% for urine samples to 96% for SCV for detecting CIN2+, which is comparable to the sensitivity of CS (overlapping 95% CI).The relative sensitivity for detecting CIN2+ was 1.00 (95% CI 0.96 to 1.04) for SCV and 0.96 (95% CI 0.91 to 1.03) for urine samples. At CIN3+, the relative sensitivity was 1.00 (95% CI 0.96 to 1.08) and 0.97 (95% CI 0.89 to 1.07) for SCV and urine samples, respectively. There were no statistical differences between the self-collected samples and the CS (McNemar’s test >0.05). The relative specificity was also similar (1.03 (95% CI 0.95 to 1.12) for SCV and 0.98 (95% CI 0.89 to 1.09) for urine samples) (McNemar’s test >0.05).The acceptability of self-sampling was evaluated by questionnaire. The women found the instructions on sample collection easy to understand and were positive about self-sampling with a preference for the urine sample.ConclusionSelf-sampling by SCV and urine is a clinically safe alternative to CS with a high degree of acceptability.