To facilitate the highest quality of HPV testing in primary cervical screening, new HPV tests must be evaluated using well annotated samples and in concordance with the International Guidelines for Human Papillomavirus Test Requirements for Cervical Screening also commonly known as the “Meijer Guidelines”. The BD Onclarity HPV assay is the first commercially developed HPV assay to use extended genotyping by single detection of six genotypes (16, 18, 31, 45, 51, 52) and three combined groups of genotypes (33/58, 56/59/66, 35/39/68). Moreover, the assay target the E6 and E7 genes of the HPV virus at DNA level and is therefore not subject to the restrictions of classical L1 assays, or of E6/E7 mRNA assays.
To assess the performance of the Onclarity assay against the Meijer guidelines we used SurePath collected screening samples from women ≥30 years of age participating in the Danish cervical cancer screening program (Ethical committee protocol: H4-2012-070, ClinicalTrials.Gov ID: NCT01671462).
The clinical sensitivity and specificity and assay reproducibility were assessed to validate the Onclarity assay according to the International guidelines. For sensitivity analysis, 61 samples with confirmed ≥CIN2 histology diagnosis were used. For specificity analysis, 1154 samples from women undergoing primary screening without ≥CIN2 diagnosis were used. The intra- and inter-laboratory reproducibility was assessed using 500 samples with known HC2 result. The inter-laboratory reproducibility was performed at the European institute of Oncology, Milan, Italy.
The sensitivity of the Onclarity assay was 96.7% (relative sensitivity compared to HC2 = 0.98) and the specificity was 89.6% (relative specificity compared to HC2 = 1.0). The Onclarity assay was shown to be non-inferior to that of the HC2 assay for both clinical sensitivity (T-test 2.0, P-value=0.02) and specificity (T-test=2.16, P-value=0.02). The Kappa value of the intra-laboratory reproducibility was 0.94 (Lower confidence bound for agreement = 96%) and for inter-laboratory agreement 0.92 (lower confidence bound for agreement = 95%), also meeting the International guidelines.
This is the first study using SurePath samples for clinical validation of any HPV assay. Comparing to HC2, the Onclarity assay obtained validation in concordance with the International guidelines, as also previously reported for the Onclarity assay using ThinPrep samples. Combined with the assays capacity for extended genotyping, the Onclarity assay is a good candidate for use in Danish cervical cancer screening where SurePath is used as collection media.