I would like to obtein at least 2kb of viral RNA of stored samples on FTA cards. For the RNA isolation of the FTA card, I already used DEPC water and "QIAamp Viral MIniElute (Qiagen)". Then, I made cDNA with the "Transcriptor First Strand cDNA Synthesis Kit (Roche)" and the "Titan One Tube RT-PCR System (Roche)".

As a result, I have only obtained products of 800pb. Do you have any suggestions for achieving 2kb or more?

Thanks