We first tested the new SCREEN platform using the same type of differential analysis involving Jurkat and U937 cells used in our original SCoPE MS paper . Hundred thousand Jurkat cells were collected by FACS sorting and underwent our typical mPOP procedure with 3-hour trypsin digest. The digested cells were separated by homemade micro high pH cartridge based on standard Thermo high pH separation spin column (Thermo-Fisher, CA) and fractionated into 5 fractions. All 5 fractions were run on the same type of gradient since single cells will be run to build a library of targeted masses. Searches were submitted to Proteome Discoverer 2.4 (Thermo-Fisher, CA) with the Byonic 3.5 (Protein Metrix, CA) search engine for combined protein Identification with Percolator as a last step and keeping all identifications at standard 1% false discovery rate (FDR). The final targeted library containing a list of 15 to 30 thousand unique peptides was created based on this run and exported as a library for targeted masses for single cell analysis runs. The analyzed three plates were FACS sorted with 4x4 (ABCD rows are J cells; EFGH rows are U cells), 2x2 (AB rows J cells; CD rows U cells; JE rows J cells; FG U cells) and 1x1 sorting methods (A raw J cells; B raw U cells; C raw J cells; D raw U cells etc.). Single cell analysis based on these three FACS sorting methods are shown in figures 3 a-d. Results from these three plates demonstrate that in each plate an average of 2,900 proteins per each of 96 wells were identified, and from the three plates a combined total of 3,006 proteins were identified. This was accomplished with a combined standard search with Proteome Discoverer 2.4 and Byonic 3.5 search engine. FDR of 1% was set for both peptide and protein levels and a scrambled database was used to estimate the true false discovery rate. The IMBR (isobaric matching between runs) technique ( ) that was recently introduced in the MaxQuant search engine will increase this number further. Another boost to the identification rate comes from CID (Collision-Induced Dissociation) type of ion trap fragmentation, which is available on the Tribrid Lumos Orbitraps (Thermo Fisher, CA). Figure shows the results of trial runs with roughly 200 cells of carrier channel that was run with an identical 90 min gradient either on the QE HF-X (Thermo Fisher, CA) instrument or the Fusion Lumos Tribrid Orbitrap instrument. CID type of fragmentation in addition to standard HCD scan for single cell analysis were used.