Resolving repeatedly borderline results of Hybrid Capture 2 HPV DNA Test using polymerase chain reaction and genotyping

The Hybrid Capture 2 HPV DNA Test (hc2) (Digene Corporation, Gaithersburg, MD) is at present the only FDA approved assay for routine detection of human papillomavirus (HPV) infections. A significant analytical inaccuracy of the hc2 near to cut-off was reported recently. To address this problem, 240 samples with repeatedly borderline/equivocal/indeterminate hc2 results (samples with repeated RLU/CO values between 0.4 and 4.0) were tested using the PGMY09/PGMY11 consensus PCR and genotyping in order to resolve their high-risk HPV status. All PGMY09/PGMY11 PCR negative samples were tested in addition using CPI/IIg consensus PCR. A false negative rate of 11.3% and false positive rate of 19.1% were recorded in the samples with repeatedly borderline hc2 results. The corresponding hc2 false reactivity rates in 95 samples selected at random which were clearly hc2 negative (samples with RLU/CO values less than 0.4) and 124 samples selected at random which were clearly hc2 positive (samples with RLU/CO values more than 4.0) were 4.2% and 5.6%, respectively. The proportion of hc2 false reactivity increased with proximity to the hc2 cut-off value. According to the results of the present study, the introduction of an hc2 grey-zone and retesting of samples with repeatedly borderline hc2 results by an alternate HPV detection method, such as the PGMY09/PGMY11 consensus PCR and genotyping, is recommended.