Effect of testing for human papillomavirus as a triage during screening for cervical cancer: observational before and after study.

OBJECTIVE: To assess the effect of introducing testing for human papillomavirus combined with liquid based cytology in women with low grade cytological abnormalities. DESIGN: Observational before and after study. SETTING: Three cervical screening laboratories, England. PARTICIPANTS: 5654 women aged 20-64 with low grade cytological abnormalities found at routine cervical screening in a pilot; 5254 similar women in the period before the pilot. INTERVENTIONS: Human papillomavirus testing combined with liquid based cytology in the management of women with borderline or mildly dyskaryotic cervical smear results compared with conventional smear tests, with immediate referral to colposcopy of women positive for human papillomavirus. RESULTS: 57.9% (3187/5506) of women tested in the pilot were positive for human papillomavirus. The rate of repeat smears fell by 74%, but the rate of referral to colposcopy for low grade cytological abnormalities more than doubled. The estimated negative predictive value of human papillomavirus testing varied between 93.8% and 99.7%. CONCLUSION: The addition of testing for human papillomavirus in women with low grade cytological abnormalities resulted in a reduction in the rate of repeat smears, but an increase in rates of referral to colposcopy.