Cross-reactivity profiles of hybrid capture II, cobas, and APTIMA human papillomavirus assays:split-sample study

BACKGROUND: High-risk Human Papillomavirus (HPV) testing is replacing cytology in cervical cancer screening as it is more sensitive for preinvasive cervical lesions. However, the bottleneck of HPV testing is the many false positive test results (positive tests without cervical lesions). Here, we evaluated to what extent these can be explained by cross-reactivity, i.e. positive test results without evidence of high-risk HPV genotypes. The patterns of cross-reactivity have been thoroughly studied for hybrid capture II (HC2) but not yet for newer HPV assays although the manufacturers claimed no or limited frequency of cross-reactivity. In this independent study we evaluated the frequency of cross-reactivity for HC2, cobas, and APTIMA assays. METHODS: Consecutive routine cervical screening samples from 5022 Danish women, including 2859 from women attending primary screening, were tested with the three evaluated DNA and mRNA HPV assays. Genotyping was undertaken using CLART HPV2 assay, individually detecting 35 genotypes. The presence or absence of cervical lesions was determined with histological examinations; women with abnormal cytology were managed as per routine recommendations; those with normal cytology and positive high-risk HPV test results were invited for repeated testing in 18 months. RESULTS: Cross-reactivity to low-risk genotypes was detected in 109 (2.2 %) out of 5022 samples on HC2, 62 (1.2 %) on cobas, and 35 (0.7 %) on APTIMA with only 10 of the samples cross-reacting on all 3 assays. None of the 35 genotypes was detected in 49 (1.0 %), 162 (3.2 %), and 56 (1.1 %) samples, respectively. In primary screening at age 30 to 65 years (n = 2859), samples of 72 (25 %) out of 289 with high-risk infections on HC2 and < CIN2 histology were due to cross-reactivity. On cobas, this was 106 (26 %) out of 415, and on APTIMA 48 (21 %) out of 224. CONCLUSIONS: Despite manufacturer claims, all three assays showed cross-reactivity. In primary cervical screening at age ≥30 years, cross-reactivity accounted for about one quarter of false positive test results regardless of the assay. Cross-reactivity should be addressed in EU tenders, as this primarily technical shortcoming imposes additional costs on the screening programmes

The Valgent4 protocol:Robust analytical and clinical validation of 11 HPV assays with genotyping on cervical samples collected in SurePath medium

BACKGROUND: The VALidation of HPV GENoyping Tests (VALGENT) is an international initiative designed to validate HPV assays with genotyping capability. The VALGENT4 protocol differs from previous VALGENT installments as the sample collection medium is SurePath, and exclusively includes samples from women ≥30 years of age which is concordant with the majority of HPV primary screening guidelines. Here we present the protocol for the fourth installment of the VALGENT framework. OBJECTIVES: In VALGENT4 11 HPV assays will be evaluated using two comparator assays based on PCR with the GP5+/6+ primers. STUDY DESIGN: Overall, the VALGENT4 panel consists of 1,297 routine samples comprised of 998 unselected, consecutive samples, of which 51 samples had abnormal cytology with 13 women diagnosed with ≥CIN2, and 299 consecutive samples enriched for ≥ASCUS cytology (100 ASCUS, 100 LSIL, 99 HSIL) with 106 ≥CIN2 upon follow up. Manipulated and DNA extracted panel samples were characterized with respect to human beta globin (HBB) and overall DNA content and composition to quality assess the panel prior to distribution to the collaborating sites. RESULT: The relative cellularity (mean CT value of HBB from the Onclarity assay) on the 1,297 LBC samples (CT=24.8) was compared with 293 un-manipulated routine cytology screening samples (CT=23.8). Furthermore, the DNA extracted panel samples was characterized using the Exome iPLEX pro assay, which reports amplifiable copies on individual samples as well as copies of five different base pair lengths. Here the data showed a slightly lower number of amplifiable DNA copies (ratio: 0.7, p=<0.01)) in the VALGENT4 panel samples compared to routine extracted cervical DNA samples CONCLUSION: The present manuscript details the manipulation, processing and quality assessment of samples used in VALGENT-4. This methodological document may be of value for future international projects of HPV test validation

Comparison of analytical and clinical performance of CLART HPV2 genotyping assay to Linear Array and Hybrid Capture 2: a split-sample study

Abstract Background: Human Papillomavirus (HPV) genotyping has an increasingly important role in cervical cancer screening and vaccination monitoring, however, without an internationally agreed standard reference assay. The test results from the most widely used genotyping assays are read manually and hence prone to inter-observer variability. The reading of test results on the CLART HPV2 genotyping assay is, on the other hand, automated. The aim of our study was to directly compare the detection of HPV genotypes and high-grade cervical intraepithelial neoplasia (CIN) by CLART, Linear Array (LA), and Hybrid Capture 2 (HC2) using samples stored in SurePath. Methods: Residual material from 401 routine samples from women with abnormal cytology was tested by CLART, LA, and HC2 (ClinicalTrial.gov: NCT01671462, Ethical Committee approval: H-2012-070). Histological outcomes were ascertained by linkage to the Danish nation-wide Pathology Data Bank. For comparison of CLART and LA in terms of genotype detection, we calculated κ-coefficients, and proportions of overall and positive agreement. For comparison of CIN detection between CLART, LA, and HC2, we calculated the relative sensitivity and specificity for high-grade CIN. Results: The κ-coefficient for agreement in detection of genotypes 16, 18, 31, 33, 35, and 51 was ≥0.90 (overall agreement: 98-99%, positive agreement: 84-95%). The values were slightly lower, but still in the &quot;substantial&quot; range for genotypes 39, 45, 52, 56, 58, 59, and several low-risk genotypes. The relative sensitivity of CLART for ≥ CIN2 and ≥ CIN3 was not significantly lower than that of LA and HC2, although CLART showed a higher specificity than HC2

Time and temperature dependent analytical stability of dry-collected Evalyn HPV self-sampling brush for cervical cancer screening

As a new initiative, HPV self-sampling to non-attenders using the dry Evalyn self-sampling brush is offered in the Capital Region of Denmark. The use of a dry brush is largely uncharted territory in terms of analytical stability. In this study we aim to provide evidence on the analytical quality of dry HPV self-sampling brushes as a function of time and temperature.We assessed the analytical stability of dry stored Evalyn brushes at three different temperatures, (4 °C, room temperature, 30 °C) and five different storage time points; T = 0 (baseline), 2, 4, 8, 16, and 32 weeks prior to HPV analysis using the BD Onclarity HPV assay.Mean Ct value of the Onclarity internal control was used as comparator of cellularity across time and temperatures, with no or only borderline statistical differences observed. HPV detection was stable throughout the five time points. In addition, analytically amplifiable DNA copy numbers and DNA fragmentation was assessed using the Agena iPLEX Exome QC assay, with no or only borderline statistical differences observed.In conclusion, the Evalyn brush is analytically stable with respect to human genomic material and HPV detection for up to 32 weeks at temperatures ranging from 4 °C to 30 °C. Keywords: Self-sampling, Dry self-sampling brushes, Analytical stability, HPV, Cervical cancer screenin

Prevalence of human papillomavirus in 5,072 consecutive cervical SurePath samples evaluated with the Roche cobas HPV real-time PCR assay

New commercially available Human Papillomavirus (HPV) assays need to be evaluated in a variety of cervical screening settings. Cobas HPV Test (cobas) is a real-time PCR-based assay allowing for separate detection of HPV genotypes 16 and 18 and a bulk of 12 other high-risk genotypes. The aim of the present study, Horizon, was to assess the prevalence of high-risk HPV infections in an area with a high background risk of cervical cancer, where women aged 23-65 years are targeted for cervical screening. We collected 6,258 consecutive cervical samples from the largest cervical screening laboratory in Denmark serving the whole of Copenhagen. All samples were stored in SurePath media. In total, 5,072 samples were tested with cobas, Hybrid Capture 2 High Risk HPV DNA test (HC2) and liquid-based cytology. Of these, 27% tested positive on cobas. This proportion decreased by age, being 43% in women aged 23-29 years and 10% in women aged 60-65 years. HC2 assay was positive in 20% of samples, and cytology was abnormal (≥ atypical squamous cells of undetermined significance) for 7% samples. When only samples without recent abnormalities were taken into account, 24% tested positive on cobas, 19% on HC2, and 5% had abnormal cytology. The proportion of positive cobas samples was higher than in the ATHENA trial. The age-standardized cobas positivity vs. cytology abnormality was 3.9 in our study and 1.7 in ATHENA. If in Copenhagen the presently used cytology would be replaced by cobas in women above age 30 years, an extra 11% of women would based on historical data be expected to have a positive cobas test without an underlying cervical intraepithelial lesion grade 3 or worse. Countries with a high prevalence of HPV infections should therefore proceed to primary HPV-based cervical screening with caution