Biblioteca Virtual en Salud

BACKGROUND:

We comparatively evaluated the performance of the conventional COBAS Amplicor HCV test v2.0 (CAM; Roche Molecular Systems, USA) and the newly developed COBAS AmpliPrep/COBAS TaqMan HCV test v2.0 (CAP/CTM; Roche Molecular Systems) for qualitative detection of hepatitis C virus (HCV) RNA in clinical samples.

METHODS:

Six hundred serum samples (100 HCV-positive, 500 HCV-negative, as determined by CAM) were selected and analysed using the new qualitative HCV RNA test, CAP/CTM qualitative test. Results were compared by confirmatory CAP/CTM quantitative test, which is a quantitative HCV RNA real-time polymerase chain reaction by Roche Molecular Systems, and anti-HCV test (Roche Diagnostics GmbH, Germany). Twenty-two additional serum samples, which gave a gray zone result by CAM, were selected for comparison.

RESULTS:

The two qualitative HCV RNA assays yielded concordant results for 586 of 600 tested samples (concordance rate, 97.7%; kappa coefficient, 0.92; 95% confidence interval [CI], 0.87 to 0.96; P<0.001). Upon re-testing by CAM, we found that the concordance rate increased to 98.2% (kappa coefficient, 0.93; 95% CI, 0.89 to 0.97; P<0.001). The additional 22 samples showing gray zone results for CAM were retested and were also tested by CAP/CTM. The results for 13 of these samples changed to negative and were now concordant with the CAP/CTM and confirmatory CAP/CTM quantitative results. For the remaining samples, the results were variable. For all the 22 samples, the results of the new CAP/CTM were in agreement with those obtained by confirmatory CAP/CTM quantitative test.

CONCLUSIONS:

The results of the two assays were in good agreement, with 97.7% concordance rate. However, CAP/CTM is more sensitive than CAM and showed no gray zone results. Therefore, it can be a more efficient and useful test for the qualitative detection of HCV RNA in clinical samples.