A comparison of ThinPrep-PreservCyt against four non-volatile transport media for HPV testing at or near the point of care.

Abstract

IntroductionThe Xpert HPV Test (Cepheid, Sunnyvale, CA) is used at point-of-care for cervical screening in a number of low-and middle-income countries (LMIC). It is validated for use with ThinPrep-PreservCyt (Hologic, Marlborough, MA) transport medium which has a high methanol content and is therefore classified as a dangerous good for shipping; making cost, transportation and use challenging within LMIC. Therefore, we compared the performance of ThinPrep against four non-volatile commercially available media for HPV point-of-care testing. MethodsTen-fold serial dilutions were prepared using three HPV cell lines each positive for 16, 18 or 31 and with each suspended in five different media types. The media types consisted of Phosphate Buffered Saline (Thermo Fischer Scientific, Waltham, MA, USA), Sigma Virocult (Medical Wire & Equipment, Wiltshire, England), MSwab (Copan, Brescia BS, Italy) Xpert Transport Media (Cepheid, Sunnyvale, USA) and ThinPrep-PreservCyt (Hologic Inc., Marlborough, MA). ResultsA total of 105 HPV Xpert tests were conducted in a laboratory setting, with 7 ten-fold dilutions of each of the 3 HPV genotypes tested in all 5 media types. The lowest HPV ten-fold dilution detected for any media, or cell line was the fifth dilution. Mswab was the only media to detect HPV to the 5th dilution across all three cell types. DiscussionMswab transport media may be a suitable alternative to ThinPrep for Xpert HPV point of care testing and increase HPV detection. A field-based, head to head comparison of both media types using the Xpert HPV assay is warranted to confirm these laboratory-based findings.