AmpFire HPV and ScreenFire RS HPV validation trial.

Abstract

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. 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. 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. 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.