Validation of Cervista HPV16/18 in SurePath Pap Specimens Using a PCR-Based HPV Genotyping Assay
Abha Khanna, Shoba Patel, Jie Feng, Linda Payne, Wei Zhang, Greg Staerkel, Ming Guo. MD Anderson Cancer Center, Houston, TX
Background: Cervista HPV 16/18 is a FDA approved HPV genotyping assay for detecting HPV16 and 18. However, validation studies of Cervista 16/18 in SurePath Pap specimen are scant. To evaluate validity of Cervista HPV16/18 in SurePath Pap specimens, we conducted a HPV genotyping study to verify the testing accuracy of Cervista HPV 16/18 using a PCR-based, commercially available HPV genotyping assay, EasyChip, in residual sample collected after routine Pap test at our cancer center.
Design: In Department of Pathology, we retrospectively selected 56 Cervista HPV positive specimens (SurePath vials with residual samples after completing routine Pap test) for the validation study. The specimens included 33 negative, 14 ASC-US, 7 LSIL and 2 HSIL Pap specimens. The patient's age ranged from 22-74 with a mean of 49 years. HPV genotyping was conducted using both Cervista HPV16/18 and PCR-based EasyChip HPV genotyping assay. The HPV genotyping results of Cervista HPV16/18 and EasyChip assay were compared.
Results: One case was disqualified based on the EasyChip internal control reading. Seven Pap specimens were tested negative by both Cervista HPV16/18 and EasyChip HPV assay. In the remaining 48 cases, Cervista HPV16/18 classified 16 positive and 32 negative cases. Of 16 Cervista HPV 16/18 positive cases, 15 were confirmed to be either HPV16 or HPV18. One specimen classified HPV16+ by Cervista HPV 16/18 showed non-HPV16 HPV types by EasyChip assay. Of 32 Cervista HPV16/18 negative specimens, 30 were confirmed to have non-16/18 HPV types by EasyChip assay. HPV18 was detected in 2 Cervista 16/18 negative specimens. The concordance between Cervista HPV16/18 and EasyChip HPV genotyping assay is 94%. Discrepancies between the two HPV genotyping assays occurred in Pap specimens with either negative (2 cases) or ASC-US (1 case) results.
Conclusions: Our HPV genotyping results support the validation of Cervista HPV16/18 as a reliable HPV16/18 genotyping assay in SurePath Pap specimens. Testing discrepancies between Cervista HPV 16/18 and EasyChip HPV genotyping assay were observed in a small fraction of specimens. Further study is required to clarify the issue.
|Pap||A9/HPV16||A7/HPV18||A9/other type||A7/other type||A5/6||Not match|