AmpFire HPV and ScreenFire RS HPV validation trial

Abstract

Objectives: The human papillomavirus (HPV) screening assays from Atila Biosystems, including the new AmpFire (14 type) and ScreenFire RS (13 type), were subjected to a series of validation tests. Methods: We used a set of samples from the Chinese Multi-Site Screening Trial (previously tested with cobas 4800 and the next-generation SeqHPV) to satisfy Meijer's criteria for clinical end-point validation. We selected 556 self-collected specimens composed of 273 high-risk HPV (hrHPV) positives and 283 hrHPV negatives on the cobas 4800 and SeqHPV. Of the 273 hrHPV-positive cases, 108 had a disease end point of cervical intraepithelial neoplasia grade 2 (CIN2) or higher, including 47 with cervical intraepithelial neoplasia grade 3 (CIN3+) or higher. We simulated the VALGENT framework for inter- and intralaboratory validation and evaluated the new 4-channel risk-stratified ScreenFire assay in a hierarchal fashion. Results: Both AmpFire and ScreenFire detected 106 (98.1%) of 108 cases with CIN2 or higher, with specificities of 56.7% and 58.1%, respectively. Intralaboratory concordance for 2 runs of AmpFire and ScreenFire was 95.13% and 96.03%, respectively, for overall hrHPV types and 99.10% and 99.46%, respectively, for HPV 16. The interlaboratory concordance of AmpFire and ScreenFire was 93.68% and 94.04% for overall hrHPV and 98.92% and 99.28%, respectively, for HPV 16. Other genotype correlation percentages were similarly high, with κs ranging from 0.86 to 0.94. The ScreenFire RS assay demonstrated excellent "genotype-specific concordance"when evaluated for "clinical guidance"in a hierarchal fashion (noting only the highest risk channel) with both the cobas 4800 and SeqHPV for less than CIN2, CIN2, and CIN3 or higher. Conclusions: The excellent intra- and interlaboratory reproducibility and the established clinical performance, together with the platforms' simplicity, make these assays particularly applicable to low-resource settings.