Comparison of the QIAGEN artus HCV QS-RGQ test with the Roche COBAS Ampliprep/COBAS TaqMan HCV test v2.0 for the quantification of HCV-RNA in plasma samples

Background: Quantification of Hepatitis C Virus (HCV)-RNA is important for the clinical management of patients undergoing antiviral therapy.

Objectives: To compare the quantification of clinical plasma samples by the Roche COBAS AmpliPrep/COBAS TaqMan HCV test v2.0 and the artus HCV QS-RGQ test.

Study design: HCV-RNA viral load in 155 plasma samples from HCV-seropositive individuals was determined using the COBAS test and retrospectively with the artus. Furthermore, a dilution series of an Acrometrix standard was tested with both tests in replicates of five to assess differences in limit of detection and precision.

Results: Two clinical samples showed inhibition using the artus test and were excluded from analysis. Of the clinical samples, 20 tested negative in both tests, 7 tested positive in the COBAS test and negative in the artus test, and 126 samples were quantified by both tests. The mean overall difference between tests (artus-COBAS) was 0.27 log IU/mL. The mean difference of quantification varied little across genotype 1a, 1b, 2b and 3a (range: +0.15 to +0.35 log IU/mL). Both tests were precise (%CV at 1000 IU/mL 1.1 and 1.8 for the COBAS and artus test, respectively).

Conclusions: The limit of detection appeared lower in the COBAS test than the artus test when analyzed from a limited number of replicates. Both tests were precise with the artus test quantifying higher than the COBAS test on average. It is therefore recommended to monitor individual patients with the same test throughout treatment.