Patch clamping is considered the "gold standard" for measuring membrane potential, but it is too slow and labor intensive to use in a primary screen. A much faster method for screening applications uses voltage-sensitive dyes on the FLIPR Fluorometric Imaging Plate Reader system. However, traditional dyes have several limitations, including slow response times and temperature sensitivity. The FLIPR Membrane Potential Assay Kits from Molecular Devices deliver higher throughput than previous automated FLIPR protocols, while showing good correlation with manual patch clamping data.