Analytical evaluation of the PapilloCheck test, a new commercial DNA chip for detection and genotyping of human papillomavirus.

Recently, a commercially available HPV DNA chip, the PapilloCheck test, developed by Greiner Bio-One, has become available for human papillomavirus (HPV) genotyping. The PapilloCheck test is a PCR-based test using a new consensus primer set targeting the E1 HPV gene. HPV oligoprobes immobilized on a DNA chip allow for the identification of 24 HPV types from the amplified product. In the present study, the analytical performance of the PapilloCheck test is compared to the Linear Array HPV genotyping test (Roche Diagnostics). Cervical specimens collected in PreservCyt (Cytyc) solution and obtained from women who presented abnormal cytological findings were tested primarily by the Hybrid Capture 2 High-Risk assay (HC2-HR, QIAGEN). A total of 144 samples were selected according to the signal intensity obtained with the HC2-HR test, expressed as RLU/CO value, and divided into 4 groups as follows: [0-1] RLU/CO (negative HC2-HR result, 34 samples); [1-5] RLU/CO (positive HC2-HR result, 30 samples); [5-40] RLU/CO (positive HC2-HR result, 40 samples); >40 RLU/CO (positive HC2-HR result, 40 samples). The concordance levels between the HC2-HR test and each of the genotyping assays was similar (88.8%) and the crude agreement between these assays was considered as "good". The detailed analysis of the discrepant results confirmed a possibly high rate of false positive results of HC2-HR test in the 1-5 RLU/CO grey zone. Genotype-specific comparison analysis was limited to the 23 HPV types detected by both genotyping assays (HPV types 6, 11, 16, 18, 31, 33, 35, 39, 40, 42, 45, 51, 52, 53, 55, 56, 58, 59, 66, 68, 70, 73 and 82). Of the 135 samples available for comparison, 91 (67.4%) showed absolute agreement between the assays (concordant genotype-specific results), 34 (25.1%) showed correspondence for some but not all genotypes detected by both assays (compatible genotype-specific results), and the remaining 10 (7.4%) samples did not show any similarity between the tests (discordant results). The majority of discordances were found in samples containing multiple HPV types and in samples harboring low amounts of HPV. For some HPV genotypes, there were slight differences in the detection rate between the two genotyping methods. The Linear Array test seemed to be more sensitive to detect HPV type 53 whereas PapilloCheck test seemed to be more sensitive to detect HPV type 56. For the other genotypes, including HPV types 16 and 18, the results obtained by the two methods did not differ significantly. In conclusion, this study shows that the PapilloCheck test and the Linear Array test give comparable results for detecting HPV in cervical specimens. However, these results also suggest that there is a need to standardize the type-specific sensitivity of genotyping methods and to evaluate their accuracy to detect multiple HPV infections. This would be a prerequisite for the use of genotyping assays in cervical cancer screening algorithms.

Evaluation of the COBAS AmpliPrep-total nucleic acid isolation-COBAS TaqMan hepatitis B virus (HBV) quantitative test and comparison to the VERSANT HBV DNA 3.0 assay.

Quantitative detection of hepatitis B virus (HBV) in serum or plasma has become the most direct and reliable method for monitoring chronic hepatitis B. Here, we report the performance characteristics of a real-time PCR hepatitis B DNA quantitative assay, the COBAS TaqMan (CTM) HBV test (Roche Diagnostics, Meylan, France), in combination with an automated DNA extraction on the COBAS AmpliPrep (CAP) instrument using the total nucleic acid isolation kit (TNAI kit), a generic reagent for nucleic acid isolation (both from Roche Diagnostics). The linearity, accuracy, and specificity of the CAP-TNAI-CTM HBV test were evaluated using various reference panels and standards (HBV panel 2004 from Quality Control for Molecular Diagnostics, OptiQuant HBV panel from AcroMetrix, WHO International Standard for HBV, and Teragenix hepatitis B genotype panel). Quantitative results show that the CAP-TNAI-CTM HBV test performed well with respect to linearity, accuracy, and reproducibility from at least 100 to 500,000 HBV DNA IU/ml. Based on the log(10) IU of HBV DNA/ml measured, the intra-assay variation ranged from 2.49% to 8.46% and the interassay variation ranged from 1.88% to 7.83%. The test was extremely sensitive and could detect samples containing HBV DNA below the reported quantification threshold (<30 IU/ml). All HBV genotypes were correctly amplified, and no cross-contamination occurred during the automated sample preparation. In addition, 402 human serum samples were tested comparatively to the VERSANT HBV DNA 3.0 assay (bDNA; Bayer Diagnostics, Puteaux, France). The viral load results of the CAP-TNAI-CTM test and bDNA were significantly correlated, but the agreement between the two tests was poor, with large differences between results for individual samples. The hands-on time was estimated to be reduced from 2.30 h with bDNA to 45 min with the CAP-TNAI-CTM test, and up to 84 samples were completely processed within a working day. Overall, the performance characteristics of the CAP-TNAI-CTM test demonstrated that it provides a high-throughput sensitive and reliable method for quantitation of HBV DNA levels in the routine molecular laboratory.