A direct comparison of methods proposed for use in widespread screening of human papillomavirus infections

We obtained cervical swabs from 397 women participating in a human papillomavirus (HPV) prevalence study. Samples were assayed for HPV infection using ViraPap expanded cocktail (detecting HPV types 6, 11, 16, 18, 31, 33, 35, 42, 43, 44, 45, 51, 52 and 56), ViraType and PCR amplifications. Consensus primers from the L1 region were used with generic and type-specific oligonucleotide probes. Additionally, the generic amplifications were analysed with a novel restriction digest scheme. Samples positive by these methods were confirmed by PCR amplification using primers from the E5 region specific for HPV types 6, 16 and 18. The presence of human DNA in the samples was verified with amplification of the human KM-19 haplotyping primers. Our results confirm that the PCR reporter oligomer hybridization method is more sensitive than ViraPap/ViraType, but encompasses a narrower range of HPV types. This is particularly true of the higher number types in the expanded cocktail. The narrow range seems to occur as the result of the reporter oligomer used in hybridization, rather than the consensus amplimer pair used. Amplification of a broader range of HPVs is seen on gels or using the restriction digest as confirmation of HPV infection. Both ViraPap and PCR methods of detection gave about a 10% rate of uninterpretable results. PCR methods indicated about 1.7 times as many positives, while showing overall agreement of 77.6% with ViraPap. Agreement on types ranged from 67% to 100%. All methods indicated large fractions of untypable HPVs).