Can I add blocking oligos to prevent the second strand synthesis of high abundant RNAs?

Yes. Blocking oligos can be added during second strand synthesis together with the TS buffer. We recommend a final concentration of 10 – 100 nM of blocking oligos during the second strand synthesis. Ideally, blocking oligos should be designed to bind close to the 3' end of the transcript(s) to block (this way exponential amplification of targeted highly abundant transcripts during the PCR is limited).