Comparative analysis of human papillomavirus detection by dot blot hybridisation and non-isotopic in situ hybridisation.

AIMS To determine the relative diagnostic performance of non-isotopic in situ hybridisation (NISH) and a dot-blot assay for detecting human papillomavirus (HPV) on exfoliated cervical cells; and to correlate the results with cytopathological assessment. METHODS Cervical smears and cytological samples were obtained from 122 patients during the same clinical examination and the presence of HPV sequences determined by NISH and dot-blot analysis, respectively. RESULTS Dot-blot analysis gave an autoradiographic signal in 15 of 121 (12.4%) cases, while NISH detected viral genomes in 38 of 114 (33.3%) cases. Even in the presence of koilocytosis, where vegetative replication of the virus occurs, NISH was positive in over twice as many cases as dot-blot analysis (NISH 90%, dot-blot 40%), while in smears within normal cytological limits, where the viral copy number is likely to be considerably lower, the differences were more striking (NISH 31%, dot-blot 5%). CONCLUSIONS These data show that NISH on cytological smears is more sensitive than a standardised dot-blot hybridisation assay for detecting HPV infection in cytological material and is therefore a more appropriate screening tool.