We aimed to determine the disagreement in primary cervical screening between four human papillomavirus assays: Hybrid Capture 2, cobas, CLART, and APTIMA. Material from 5,064 SurePath samples of women participating in routine cervical screening in Copenhagen, Denmark, was tested with the four assays. Positive agreement between the assays was measured as the conditional probability that the results of all compared assays were positive given that at least one assay returned a positive result. Of all 5,064 samples, 1,679 (33.2%) tested positive on at least one of the assays. Among these, 41% tested positive on all four. Agreement was lower in women aged ≥30 years (30%, vs. 49% at <30 years), in primary screening samples (29%, vs. 38% in follow-up samples), and in women with concurrent normal cytology (22%, vs. 68% with abnormal cytology). Among primary screening samples from women aged 30–65 years (n = 2,881), 23% tested positive on at least one assay, and 42 to 58% of these showed positive agreement on any compared pair of the assays. While 4% of primary screening samples showed abnormal cytology, 6 to 10% were discordant on any pair of assays. A literature review corroborated our findings of considerable disagreement between human papillomavirus assays. This suggested that the extent of disagreement in primary screening is neither population- nor storage media-specific, leaving assay design differences as the most probable cause. The substantially different selection of women testing positive on the various human papillomavirus assays represents an unexpected challenge for the choice of an assay in primary cervical screening, and for follow up of in particular HPV positive/cytology normal women.

BackgroundHuman papillomavirus (HPV) genotyping assays are becoming increasingly attractive for use in mass screening, as they offer a possibility to integrate HPV screening with HPV vaccine monitoring, thereby generating a synergy between the two main modes of cervical cancer prevention. The Genomica CLART HPV2 assay is a semi-automated PCR-based microarray assay detecting 35 high-risk and low-risk HPV genotypes. However, few reports have described this assay in cervical screening.An aim of the present study, Horizon, was to assess the prevalence of high-risk HPV infections in Copenhagen, Denmark, an area with a high background risk of cervical cancer where women aged 23-65 years are targeted for organized screening.MethodsMaterial from 5,068 SurePath samples of women participating in routine screening and clinical follow-up of cervical abnormalities was tested using liquid based cytology, CLART HPV2 and Hybrid Capture 2 (HC2).ResultsAt least one of the 35 defined genotypes was detected by CLART in 1,896 (37%) samples. The most frequent high-risk genotypes were HPV 16 (7%), HPV 52 (5%), and HPV 31 (4%). The most frequent low-risk genotypes were HPV 53 (5%), HPV 61 (4%), and HPV 66 (3%). Among 4,793 women targeted by the screening program (23-65 years), 1,166 (24%) tested positive for one or more of the 13 high-risk genotypes. This proportion decreased from 40% at age 23-29 years to 10% at age 60-65 years. On HC2, 1,035 (20%) samples were positive for any high-risk and thus CLART showed a higher analytical sensitivity for 13 high-risk HPV genotypes than HC2, and this was found in all age-groups and in women normal cytology.ConclusionsCLART performed well with a positive reproducibility for high-risk genotypes of 86%, and a negative reproducibility of 97%. This report furthermore updates the genotype distribution in Denmark prior to the inclusion of the HPV-vaccinated cohorts into the screening program, and as such represents a valuable baseline for future vaccine impact assessment.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2334-14-413) contains supplementary material, which is available to authorized users.

In women aged ≥30 years, Human Papillomavirus testing will replace cytology for primary cervical screening. We compared Hybrid Capture 2 (HC2), cobas, CLART, and APTIMA HPV assays with cytology on 2869 SurePath samples from women undergoing routine screening at 30–65 years in Copenhagen, Denmark. Women with cytological abnormalities were managed according to routine recommendations, with 92% completeness. Those with cytology-normal/HPV-positive samples (on any of the four assays) were invited for repeated cytology and HPV testing in 1.5 year, and 58% had additional testing. HPV testing detected more ≥CIN3 than cytology (HC2: 35, cobas, CLART: 37, APTIMA: 34, cytology: 31), although statistically the differences were not significant. Cobas and CLART detected significantly more ≥CIN2 than cytology (cobas, CLART: 49, cytology: 39). The proportion of women with false-positive test results (positive test results without ≥CIN3) varied between 3.3% with cytology and 14.9% with cobas. All HPV assays led to significantly more false-positive tests, whereas compared to HC2 cobas and CLART were associated with a significantly higher and APTIMA with a significantly lower proportion. Detection of CIN1 was particularly increased for the three DNA assays. With APTIMA combined with cytological triage, about 20% more women were referred for colposcopy than with cytology screening. With the three DNA assays, the increase was ≥50%. The number of women with repeated testing was twice as high with APTIMA and almost five times as high with cobas compared to cytology. To our knowledge, Horizon was the only study set in routine practice that compared more than two HPV assays in the same women while also ascertaining the histological status of women with normal cytology/HPV-positive test results. HPV-based screening of Danish women aged 30–65 detected more high-grade CIN but decreased the screening specificity, and increased the demand for additional testing.