Qiagen's Total RNA and Viral RNA kits use the same underlying silica technology so the only difference I see is the sample type that is suggested that you use (cell-based vs cell free) and the addition of carrier RNA, which may help isolate low concentrations of viral RNA in a sample. Is there anything else that would direct the Viral RNA kit toward vRNA and away from mRNA? I have a bunch of Viral RNA extraction reagents and I would like to target a cellular gene that may be in an environmental sample - "environmental RNA (eRNA)". The Viral RNA kit might work well in this case since the cellular RNA would exist outside of a cell. Thanks!