Optimizing delivery conditions is a critical step in any experiment utilizing the CRISPR/Cas9 system. The Invitrogen™ LentiArray CRISPR Positive Control Lentivirus gRNA against HPRT is a highly efficient gRNA validated in multiple human cell lines that has achieved editing efficiencies of greater than 80%. It can be used to rapidly determine ideal delivery conditions in order to achieve maximum editing efficiency in your cell model of choice. This construct also expresses emGFP to provide a visual readout of successful transduction that can be used in determining Multiplicity of Infection (MOI).