Development and Characterization of the cobas Human Papillomavirus Test

Abstract

The cobas human papillomavirus (HPV) test, approved by the FDA in April 2011, is a fully automated assay for the detection of 14 high-risk (hr) HPV genotypes from cervical specimens collected in liquid-based cytology medium using real-time PCR amplification of the L1 gene and TaqMan probes. Results are simultaneously reported as positive or negative for the pooled 12 oncogenic HPV types (HPV31, -33, -35, -39, -45, -51, -52, -56, -58, -59, -66, and -68) from channel 1, with HPV16 and HPV18 genotypes read individually from channels 2 and 3. A fourth channel detects the human β-globin gene as a control for sample adequacy and assay inhibition. To optimize clinical sensitivity and specificity, cutoff values (cycle thresholds [C(T)]) were established for each channel based on the detection of cervical intraepithelial neoplasia grade 2 (CIN2) or greater (≥CIN2). For women aged ≥21 years with cytology results indicating atypical squamous cells of undetermined significance (ASC-US), CT values provided a sensitivity of 90% (95% confidence interval [CI], 81.5% to 94.8%) for the detection of ≥CIN2 and a specificity of 70.5% (95% CI, 68.1% to 72.7%). The analytic sensitivity (limit of detection) ranged from 150 to 2,400 copies/ml, depending on genotype. The analytic specificity, evaluated by comparing the HPV result with a combined comparator of Sanger sequencing and the Qiagen digene HC2 high-risk HPV DNA test (hc2), demonstrated overall positive agreement of 96.3% for 14 hrHPV types in women with ASC-US cytology results who were aged ≥21 years and 86.1% in women with NLIM (negative for intraepithelial neoplasia or malignancy) cytology who were aged ≥30 years. These and other performance validation studies demonstrate that the cobas HPV test is a fully automated and clinically validated robust test.