Commentary: Detection of low level viraemia in telaprevir-based triple therapy for hepatitis C virus - Authors' reply

摘要

We appreciate the interest of Dr Elsharkawy in our work and thank him for his comment. Dr Elsharkawy pointed out that a post hoc analysis of phase III data demonstrated the importance of low levels of detectable but not quantifiable hepatitis C virus (HCV) RNA results for triple therapy with first generation HCV protease inhibitors (PIs). A major difference to the Harrington study was indeed that we compared the HCV RNA results between three different test systems. One of our key findings was that, although the HPS/TAQMAN_Test_v2.0 tended to have the lowest sensitivity, a significant number of HCV RNA positive samples were missed by testing HCV RNA only once, no matter which assay was used. Similar results have to be expected for all available HCV RNA assays due to the problem in classifying samples with HCV RNA titres below the assays so-called limit of detection (LLD), where it is simply a matter of chance whether very low levels of HCV RNA are detected or not. We conclude that the likelihood to identify positive samples with HCV RNA levels below the LLD should increase by the number of repeated tests, even with the same assay, which is certainly more feasible than using different assays.