I am not aware of the HCV ELISA test being used to detect the "strength" of a virus, whatever that means. Certain results from it can indicate how likely it is you truly have HCV (in other words, that the antibody test was not a false positive). Perhaps that is what your doctor meant. In that case, a qualitative RNA test does not need to be done. You can go straight to measuring the actual viral count and determining the genotype. If you've already had the RNA test, which detects the actual virus itself (I presume it's the qualitative one that just tells if you are positive or negative), then you don't really need the ELISA test, which is an antibody test. You need to know just how much virus is in your blood and what the strain is, which are more specific RNA tests. Hope this answers your query.