Abstract: A method for quantitatively determining the level of protein kinase C (PKC) activation in cells in response to exposure to a PKC activating compound using a moving optical gradient including the steps of providing a series of cell samples, exposing the series of cell samples to different concentrations of the PKC activating compound, moving the cells and the optical gradient relative to each other so as to cause displacement of at least some of the cells, measuring the displacement of at least a portion of the displaced cells for each of the different concentrations, generating a dose response curve of the measured displacement as a function of the concentration of the PKC activating compound, and determining the potency of the PKC activating compound from the dose response curve. The method can also be used to determine the relative efficacy of the PKC activating compound as compared to a standard compound.