The Hybrid Capture II assay (hc2; QIAGEN, Inc) for high-risk human papillomavirus (hrHPV) is an in vitro nucleic acid hybridization assay using chemiluminescence for the qualitative detection of hrHPV DNA in cervical samples. Results are reported as a ratio of relative light units (RLUs) to a cutoff value based on a positive control. Specimens with RLU ratios of 1.0 or higher are scored positive for hrHPV. We tested the hypothesis that hrHPV positives with low-positive RLU ratios (1-10) had a lower prevalence of cervical intraepithelial neoplasia 2,3 (CIN 2,3) on histologic follow-up.
Materials and Methods.
Relative light unit ratios for 388 consecutive hrHPV-positive cervical cytologic specimens interpreted as atypical squamous cells of undetermined significance (ASCUS) were reviewed. Individual RLU ratios were compared with outcome histologic diagnosis in cases with colposcopic follow-up and tissue sampling (biopsy and/or endocervical curettage; n = 236).
Of 236 cases with histologic follow-up, 63 had RLU ratios in the range of 1 to 10; of these, 53 (84.1%) were negative for CIN, 7 (11.1%) had CIN 1, 1 (1.6%) had CIN of uncertain grade, and 2 (3.2%) had CIN 2,3. The difference in CIN 2,3 outcome between RLU ratios of 1 to 10 (3.2%) versus over 10 (17.3%) was significant (p =.0047). The difference in prevalence of CIN 1 was not significant (p =.67).
An RLU ratio of 10 or less was associated with a significantly lower prevalence of CIN 2,3 on biopsy outcome after a Pap test result of ASCUS. The much lower prevalence of underlying CIN 2,3 in patients who are weakly HPV-positive may justify modification of the management algorithm for this subset of women with ASCUS.