ABSTRACT
Objectives: To examine the comparative stochasticity profile of six commercial SARS-CoV-2 nucleic acid amplification tests (NAATs) and how this may affect retesting paradigms. Methods: Commercial quality control (QC) material was serially diluted in viral transport media to create a panel covering 10-10,000 copies/ml. The panel was tested across six commercial NAATs. A subset of high cycle threshold results was retested on a rapid PCR assay to simulate retesting protocols commonly used to discriminate false positives. Results: Performance beyond the LOD differed among assays, with three types of stochasticity profiles observed. The ability of the rapid PCR assay to reproduce a true weak positive specimen was restricted to its own stochastic performance at the corresponding viral concentration. Conclusion: Stochastic performance of various NAATs overlap across low viral concentrations and affect retesting outcomes. Relying on retesting alone to discriminate false positives risk missing true positives even when a more sensitive assay is deployed for confirmatory testing.
ABSTRACT
This study demonstrates that the clinical sensitivity, specificity, and reproducibility of the novel cobas human papillomavirus (HPV) test on the cobas 6800 system for high-risk HPV types fulfills the criteria for use in population-based cervical screening. The criteria were formulated by an international consortium, using the cobas 4800 HPV test as a validated reference assay. The cobas HPV test detected over 98% of histologically confirmed cervical intraepithelial neoplasia grade 2+ (CIN2+) lesions in women age 30 years or older, with a specificity of 98.9% compared with the reference cobas 4800 test. Both the intra- and interlaboratory agreement for the cobas HPV test were 98%. The clinical performance of the cobas HPV test is comparable to those of longitudinally validated HPV assays and fulfills the criteria for its use in primary cervical screening.
