Clinical Impact of the Analytical Specificity of the Hybrid Capture 2 Test: Data from the New Technologies for Cervical Cancer (NTCC) Study

Abstract

The Hybrid Capture 2 (HC2) test targets 13 human papillomavirus (HPV) types. Here, cross-reactivity with non-HC2-targeted HPV types is described. We aimed to define the proportion of HC2-positive women who had negative results with HC2-targeted HPV types and estimate its determinants and impact on women's health management. The New Technologies for Cervical Cancer (NTCC) trial was followed in two predetermined phases. Women in the experimental arm were tested for the presence of HPV DNA by HC2 following a sample collection in PreservCyt (first phase) or Digene specimen transport medium (STM) (second phase). HPV genotyping was performed on DNA samples from HC2-positive women by PCR with GP5(+)/GP6(+) primers and reverse line blot (RLB) hybridization. Untyped samples were submitted to direct sequencing or restriction fragment length polymorphism. Multivariate logistic regression analysis estimated the adjusted odds ratios (ORs) between the presence of HC2-targeted types and age, viral load, and type of transport medium. Out of 2,920 HC2-positive samples, 2,310 (79.1%) were positive on RLB for HC2-targeted types, 396 were positive (13.6%) for only non-HC2-targeted types (mostly represented by HPV-53, HPV-66, and HPV-70), and in 214 (7.33%) samples, no HPV types were detected. The probability of detecting HC2-targeted types increased with increasing viral load expressed as the relative light unit/positive-control specimen ratio (RLU/PC) (OR for unitary increase of log RLU/PC, 1.35; 95% confidence interval [CI], 1.30 to 1.42) and with STM versus PreservCyt (OR, 1.56; 95% CI, 1.25 to 1.84). If only the samples containing HC2-targeted types tested positive, the positive predictive value (PPV) would have increased from 7.0% (95% CI, 6.1% to 8.0%) to 8.4% (95% CI, 7.3 to 9.6), although 4.9% (95% CI, 2.4% to 8.8%) of cervical intraepithelial neoplasia grade 2(+) (CIN2(+)) cases would have been missed. In conclusion, STM use and an increased cutoff would reduce the HC2 analytical false-positive rate and increase the positive predictive value for high-grade CIN. The gain in clinical sensitivity by detecting non-HC2-targeted HPV types is limited.