We have trying to perform a CRISPR screen with a new library. Using NGS we confirmed the presence of all 85K gRNA in our plasmid library. However, we only detected about 3000 in the transduced cells. At this point we are thinking that either the cells did not transduce well or the plasmid library did not package efficiently into LV particles. For the first option, we plan to repeat transduction in multiple cell lines. However, what is the best way to figure out the gRNA coverage in LV suspension? Thanks.