Development and Validation of a Preanalytic Procedure for Performing the cobas HPV Test in SurePath Preservative Fluid

Abstract

The formation of chemical cross-links between nucleic acids and proteins in formalin-containing media presents challenges for human papillomavirus (HPV) testing of cervical samples collected in SurePath Preservative Fluid. A preanalytic process involving addition of a nucleophilic buffer and heating the sample to 120°C was developed to reverse the effects of cross-linking and improve nucleic acid accessibility for the cobas HPV Test in SurePath. Cycle threshold (C) values for cobas HPV detection were evaluated over time and various temperatures, and mean C differences between pretreated and both untreated SurePath samples and those collected in PreservCyt were assessed. Without pretreatment, low viral levels (1 × limit of detection) of HPV were no longer detectable by 7 days. For prospectively collected specimens, mean (95% CI) C differences between pretreated and untreated samples indicated enhanced HPV DNA recovery in all categories of treated samples: -2.58 (-3.16 to -2.01), -2.63 (-3.62 to -1.64), and -3.39 (-4.95 to -1.82), respectively, for other 12 high-risk HPV types, HPV16, and HPV18. Furthermore, mean (95% CI) C differences of pretreated SurePath samples were comparable to simultaneously collected PreservCyt samples: -0.48 (-0.98 to 0.02) and -0.23 (-0.93 to 0.46), respectively, for HPV16 and HPV18; a borderline significant difference [-0.35 (-0.57 to -0.13)] was observed for other 12 high-risk HPV types. This preanalytic procedure therefore ensures a validated, safe, and accurate method for cobas HPV testing in SurePath.

Quantitative Proteomic Analysis Identifies AHNAK (Neuroblast Differentiation-associated Protein AHNAK) as a Novel Candidate Biomarker for Bladder Urothelial Carcinoma Diagnosis by Liquid-based Cytology

“…In this study, all liquid-based cytology samples were prepared using the preservation solution, "CytoRich Clear Preservative Fluid", which contains a mixture mainly composed of ethanol with small amounts of methanol and isopropanol, and has been confirmed to achieve superior DNA preservation for genomic analysis, compared with the conventional 95% ethanol-based fixation used in previous studies (27,28). After scraping off of all cytological material within an encircled spot, our single-shot MS analysis achieved identification of a total of 4,839 proteins in a relatively short time without fractionation, which is a comparable depth of proteome coverage to that reported in a previous study (29).…”

Clinical validation of full genotyping CLART® HPV4S assay on SurePath and ThinPrep collected screening samples according to the international guidelines for human papillomavirus test requirements for cervical screening

“…However, correct preanalytical treatment of samples counters the impact of formaldehyde [44]. Furthermore, studies with BD Onclarity [16,17], Hologic Aptima [45,46], Roche cobas [47,48] and Genomica CLART HPV2 [49] have previously shown that Sure-Path collected samples can safely be used for HPV analysis. ThinPrep collected LBC medium on the other hand does not contain formaldehyde and consequently is considered less challenging with respect to HPV testing.…”

Clinical validation of full genotyping CLART® HPV4S assay on SurePath and ThinPrep collected screening samples according to the International Guidelines for Human Papillomavirus Test Requirements for Cervical Screening

“…Furthermore, studies with BD Onclarity (16,17), Hologic Aptima (45,46), Roche cobas (47,48) and Genomica CLART HPV2 (49) have previously shown that SurePath collected samples can safely be used for HPV analysis. ThinPrep collected LBC medium on the other hand does not contain formaldehyde and consequently is considered less challenging with respect to HPV testing.…”