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Evaluation of a human papillomavirus assay in cervical screening in Zimbabwe
S D Womack1, Z M Chirenje, P D Blumenthal
1Department of Molecular Microbiology and Immunology, Johns Hopkins School of Hygiene and Public Health, Baltimore, Maryland 21205-2179, USA.
Objective:
To determine the utility of an assay for high risk genital human papillomavirus (HPV) in cervical screening in Zimbabwe, Africa.
Design:
Cross-sectional study.
Setting:
Harare, Zimbabwe.
Population:
Zimbabwe women (n = 2,140), 25 to 55 years old, recruited in clinics in Chitungwiza and Greater Harare.
Methods:
Genital specimens were assessed for HPV, using the HPV DNA test Hybrid Capture II (probe B). Further assessment of the women was conducted using colposcopy and biopsy as indicated. High grade squamous intraepithelial lesions were diagnosed in 215 women. Colposcopy and/or biopsy showed low grade lesions in 346 women.
Results:
The overall prevalences were: 42 x 7% for HPV, 10% for high grade squamous intraepithelial lesions and 16% for low grade lesions. Prevalence for HPV decreased significantly with increase in age (P for trend < 0 x 0001) and increased significantly with increasing disease severity, from 35% in normal women, to 53% in women with low grade lesions and 81% in women with high grade lesions (P for trend < 0 x 001). In specimens positive for HPV, the amount was 14-fold higher in women with high grade lesions compared with normal women. In screening for high grade lesions the assay for HPV had a sensitivity of 81% (CI 75%-86%); sensitivity for low grade lesions was 64% (CI 60%-68%). Specificity was 62% (CI 59%-64%) for high grade lesions and 65% (CI 62%-67%) for low grade lesions. The positive predictive value was 19% (CI 17%-22%) for high grade lesions and 39% (CI 36%-42%) for low grade lesions.
Conclusion:
For high grade squamous intraepithelial lesions the sensitivity of the Hybrid Capture II HPV DNA test was high, but the specificity was relatively low. The test may therefore be most useful in conjunction with other screening tests.