I found methods to study influence of different drugs on viability of tumor cell lines. In this case the common approach is to estimate EC50/IC50. Different concentrations are added to cells and cell viability is checked in a definite periods of time. But if the question of study is the effect of an inhibitor of glucose transport on function of PBMC? (I am going to check the concentration of cytokines in the medium and intracellular cytokines production in T-lymphocytes) Should I check influence of different concentrations of this substance on cell viability first as well? Or I should rather check the effects of this compound on glucose consumption by cells to identify the concentrations to be used in the study?