Comparison between Xpert® and COBAS® TaqMan® for the measuring of viral load of hepatitis B and C viruses

Abstract

The measurement of viral load (VL) of hepatitis B (HBV) and C (HCV) viruses is essential in the follow-up of patients with antiviral therapy. The most widely used methodology for this determination is COBAS®-TaqMan®. Recently, the Xpert® technology was developed and needs to be evaluated. To compare the measurement of the VL of HBV and HCV by Xpert® methodology with COBAS®-TaqMan® as a reference method. 39 serum samples from patients with HBV and 39 with HCV, previously quantified by COBAS®-TaqMan®, were analyzed using Xpert® and the results were compared using Deming regression and Bland-Altman plot. There was a high correlation between Xpert® and COBAS®-TaqMan®. For HBV, the Deming equation was XpertHBV = 0.44 + 0.99xCOBASTaqManHBV, with a correlation coefficient of 0.94 and a difference between means of -0.401 log (95% CI: -1.985 to 1.183). For HCV, the Deming equation was XpertHCV = 0.36 + 0.87x COBASTaqManHCV, with a correlation coefficient of 0.98 and a difference between means of0.328 log10 (95% CI: -0.449 to 1.105). The new Xpert® system shows a good correlation with COBAS®-TaqMan® for the measurement of the VL of HBV and HCV, being a good alternative for the follow-up of patients under treatment.