Improved detection of viral RNA isolated from liquid-based cytology samples

Molecular diagnosis requires the ability to obtain high-quality nucleic acids that are representative of the disease state. We evaluated the recovery and detection of limiting amounts of viral oncogenic RNA from cells fixed in liquid-based cytology media. Serial dilutions of a human papillomavirus (HPV)-positive cell line fixed in a liquid media was used as a model system. Total nucleic acid (TNA) extraction produced RNA with clearly visible ribosomal bands even after one year of storage. These TNA extracts, treated with DNase-I, were used in an RT-PCR assay for HPV-16 E6-E7 oncogenic transcripts. With chemiluminscent Southern blot detection, samples with one HPV-positive cell in 30,000 were consistently detected. PreservCyt-fixed cells can yield RNA suitable for molecular assays even after one year of storage.