I tried to integrate transgene into mammalian cell line using CRISPR technology. After 48 hours of transfection, I isolated genomic DNA using SP-DNA tissue kit (SP-DT) http://www.kurabo.co.jp/bio/English/product/products.php?M=T&TID=21 and got positive result for integration after PCR confirmation (as my primers are specific to transgene). But I was just wondering that is it possible that this kit isolated the transfected plasmid DNA to show me false positive result? I could not find specific information about plasmid isolation using that kit as they mentioned only DNA (which (I THINK) could be either plasmid or genomic). Is there any easy way to troubleshoot this except designing new primers or southern blotting? Should I isolate gDNA after 72-96 hours when most of the plasmid DNA is diluted out? Thank you.