Clinical evaluation of the cartridge-based GeneXpert human papillomavirus assay in women referred for colposcopy

Abstract

High-risk human papillomavirus (hrHPV) testing is now being introduced as a potential primary screening test for improved detection of cervical precancer and cancer. Current U.S. Food and Drug Administration-approved tests are batch tests that take several hours to complete. A rapid, non-batch test might permit point-of-care (POC) testing, which can facilitate same-day screen and management strategies. For a non-batch, random-access platform (GeneXpert; Cepheid, Sunnyvale, CA), a prototype hrHPV assay (Xpert) has been developed where testing for 14 hrHPV types can be completed in 1 h. In the first clinical evaluation, Xpert was compared to two validated hrHPV tests, the cobas HPV test (cobas, Roche Molecular Systems) and Hybrid Capture 2 (hc2, Qiagen), and to histologic outcomes using specimens from colposcopy referral populations at 7 clinical sites in the United States (n = 697). The sensitivity of Xpert for cervical intraepithelial neoplasia grade 2 or more severe diagnoses (CIN2+) (n = 141) was equal to that of cobas (90.8% versus 90.8%, P = 1) and greater than that of hc2 (90.8% versus 81.6%, P = 0.004). Xpert was more specific than cobas (42.6% versus 39.6%, P = 0.02) and less specific than hc2 (42.6% versus 47.7%, P < 0.001). Similar results were observed for cervical intraepithelial neoplasia grade 3 or higher (CIN3+) (n = 91). HPV16 detection by Xpert identified 41.8% of the CIN2+ specimens with a positive predictive value (PPV) of 54.6%. By comparison, HPV16 detection by cobas identified 42.6% of the CIN2+ specimens with a PPV of 55.0%. hrHPV detection by the Xpert demonstrated excellent clinical performance for identifying women with CIN2+ and CIN3+ that was comparable to that of currently available clinically validated tests.

FIG 1

Sensitivity of Xpert (Cepheid), cobas (Roche), and hc2 (Qiagen) for cervical intraepithelial neoplasia grade 3 (CIN2) or more-severe CIN (CIN3+) (A), percent positive specimens (B), and positive predictive value for CIN3+ by age group (C).