Performance of Commercial Reverse Line Blot Assays for Human Papillomavirus Genotyping

The performance of three line blot assays (LBAs), the Linear Array HPV genotyping assay (LA) (Roche Diagnostics), INNO-LiPA HPV Genotyping Extra (LiPA) (Innogenetics), and the reverse hybridization assay (RH) (Qiagen), was evaluated using quantitated whole genomic human papillomavirus (HPV) plasmids (types 6, 11, 16, 18, 31, 33, 35, 39, 51, 52, 56, 58, 59, and 68b) as well as epidemiologic samples. In a plasmid titration series, LiPA and RH did not detect 50 international units (IU) of HPV type 18 (HPV18) in the presence of 5 × 104 IU or more of HPV16. HPV DNA (1 to 6 types) in the plasmid challenges at 50 IU or genome equivalents (GE) were identified with an accuracy of 99.9% by LA, 97.3% by LiPA, and 95.4% by RH, with positive reproducibility of 99.8% (kappa = 0.992), 88.2% (kappa = 0.928), and 88.1% (kappa = 0.926), respectively. Two instances of mistyping occurred with LiPA. Of the 120 epidemiologic samples, 76 were positive for high-risk types by LA, 90 by LiPA, and 69 by RH, with a positive reproducibility of 87.3% (kappa = 0.925), 83.9% (kappa = 0.899), and 90.2% (kappa = 0.942), respectively. Although the assays had good concordance in the clinical samples, the greater accuracy and specificity in the plasmid panel suggest that LA has an advantage for internationally comparable genotyping studies.