While cell growth is important, it is equally important to determine if the iPSCs maintained phenotypic fidelity after passaging. In this experiment, we determined the pre-passaging levels of iPSC surface markers CD44, Oct4, Sox2 and SSEA-4 using flow cytometry. We grew the cells for three passages and then looked at the levels of the same four surface markers. In this figure, the top row shows flow cytometry data pre-passaging and the second row is post three passages. The summary of the data indicates that the iPSCs maintained consistent surface marker expression after several passages and several weeks in culture with Physiologix XF growth factor concentrate.