Evaluation of the new cobas® HCV genotyping test based on real-time PCRs of three different HCV genome regions.

Background: Determination of the hepatitis C virus (HCV) genotype and discrimination between HCV subtypes 1a and 1b is still mandatory prior to anti-HCV treatment initiation. The aim of this study was to evaluate the performance of the recently introduced cobas\(R) HCV GT assay (Roche) and to compare it to two comparator assays. Methods: The cobas (R) HCV GT assay is based on primerspecific real-time polymerase chain reaction (PCR). For comparison, the TRUGENE (R) HCV 5'NC Genotyping Kit (Siemens) and the VERSANT (R) HCV Genotype 2.0 Assay (Siemens) were employed. Accuracy of the new assay was determined using proficiency panels. For clinical evaluation, 183 residual clinical samples obtained from patients with chronic hepatitis C infection were included. Results: When accuracy was tested, panel members containing HCV subtypes 1a, 1b, and 3a were identified as expected; however, the new assay failed to identify low titer panel members containing HCV subtype 5a correctly. Of 183 clinical samples, 160 gave concordant results. For seven samples, an indeterminate result was reported with the cobas (R) HCV GT assay and the remaining 16 samples were found discordant with one of the comparator assays. When time-to-results of the assays were compared, the new assay showed shorter total time and similar handson time per sample. Conclusions: The cobas (R) HCV GT assay showed a good performance and proved to be suitable for use in the routine diagnostic laboratory. Due to the high level of automation, fast and reliable results are obtained with short hands-on time.