HPV testing in urine has been proposed for monitoring impact of vaccination, follow-up of treatment and/or reaching women not participating in a cervical cancer screening programme. The use of Colli-Pee® (Novosanis, Belgium) and UCM (Urine Collection Medium, UAntwerp, Belgium) has enhanced the analytical detection of HPV DNA in female urine. The aim of this study was to check compatibility with Colli-Pee® collected, UCM preserved urine and compare performance of the Roche Cobas® 4800 and 6800 HPV assays. In addition, a pilot on impact of different preservatives on HPV detection onto the cobas® 6800 System was conducted.
Forty-four Colli-Pee® collected, UCM preserved urine samples were analysed. Thirty-two of these samples originated from a cohort of women participating in a therapeutic HPV vaccination trial. These samples were collected by the participants at home and were send uncooled by postal mail to the University of Antwerp. All samples were characterised by an in-house HPV type specific (TS) qPCR method (UAntwerp, Belgium) and or by the Optiplex HPV genotyping kit (Diamex, Heidelberg, Germany). We further tested 15 urine samples of which 10 were previously positive for HPV 16 and/or 18. These samples were stored for 3 days at RT without preservative, with UCM or with Roche preservative.
This pilot study demonstrates that the Roche cobas® HPV 6800 assay performs well with the Colli-Pee® collected, UCM preserved urine samples. All 44 samples were positive for the Roche beta-globin internal control. Comparing CT values of the cobas® 4800 HPV assay with the cobas® 6800 HPV assay showed that lower CT values were observed for the IC control as well as for the HPV 16, HPV 18 and other HR HPV types in the cobas® 6800 System. Compared to cobas®4800 HPV assay an additional 7 samples were positive for HPV 16.
A correlation between the Ct (cycle threshold) values obtained with Cobas® 6800 HPV and the in-house TS qPCR is observed for human DNA and HPV DNA. This further confirms the compatibility of the Roche assay and the Colli-Pee® collected, UCM preserved urine.
The impact of preservative was most noted on the Internal Control, 5 of the 15 samples without preservative were reported invalid.
We confirm that the cobas®HPV 6800 assay is compatible with Colli-Pee® collected, UCM preserved urine. The analytical sensitivity seems to be increased compared to the cobas® 4800 system. The importance of a preservative is reconfirmed.