The newly developed SCREEN platform has been successfully applied to the classical single cell proteomics experiment of separating Jurkat cells from U937 human blood cancer cells. We show that SCREEN performs better that the original SCoPE method and demonstrate the increased depth of the proteome coverage that can be achieved by the new SCoPE X acquisition method using a library targeted acquisition (LTA) approach. Furthermore, we used Jurkat cells treated with PMAi to show that SCREEN allows not only a clear distinction between treated and untreated cell populations based on their proteome shift, but also displays a digital response. It is encouraging to not only observe differences in cell response due to drug treatment, but when targeted approaches are applied to the same cells, we can also see the time course of drug treatment. SCREEN targeted analysis was focused only on the 95 biologically important proteins that presented as having low abundances per cell count. Our platform was able to distinguish the cells based on time and duration of the same drug treatment due to the different pathways that were activated. This important result highlights that with this new targeted approach we have achieved a significant milestone in single cell proteome analysis (SCPA), that is, we now have the ability to concentrate on a specific part of the proteome that is biologically relevant to a given study and can quantify low abundant proteins despite the presence of an embedded highly abundant structural proteome. Additional experiments demonstrate that SCREEN was able to observe a difference between drug susceptible leukemia cancer cells and resistant cells from the same leukemia cell line. All these results clearly highlight that the newly developed SCREEN platform is a powerful analytical tool that can be employed in the study of biologically complex systems to reveal unique drug response signatures based on changes in the proteome of each individual cell. In the field of single cell proteome analysis and single cell biology, this new development is a significant leap towards impactful clinical application since we now have the ability to critically study cancer cell heterogeneity and drug resistance mechanisms of cells in response to drugs and combinations of drugs based on proteome changes at single cell resolution. on QE HFX instrument with identical gradient that is used to do analysis of sing cell run on both columns that were installed on a tandem Ultimate 3000 nano HPLC system. Despite the fact that PharmaFluidics columns are chip-based production and have identical dimensions and dead volumes, but internal dead volume of each valve/pump and some extra tubing between two 10 port vales Valco (Houston, TX) creates a unique elution times for each column/pump pair. To resolve this issue two independent libraries were prepared for each pair of column/pump. Alternative single cell library can be created with large 10 min windows to accommodate both pumps elution times that are usually differ by 3-7 minutes across the LC gradient. To improve this situation and create an ability to use general library for tandem pump acquisition that would be applicable to all runs requires a rewiring of an LC system. this column independent mode where 1 valve is used for all trapping runs and second valve is used for all elution analytical runs, this type of tandem pump acquisition mode will be column independent (assuming the same dead volumes for both analytical columns) and allows very tight windows for tandem library that will enable even a larger targeted list across 90 min gradients (data not shown, work in progress). Currently we been able to upload up to 30 thousand unique peptides into the targeting list on QE HFX Orbitrap for LTA runs based on unique peptide identification from combined fractionated ID of carrier channel.