CyBi-Lumax flash HT flash luminescence reader, for functional screening of G-protein coupled receptors and calcium channels, features a new 16-channel dispenser that enables flash luminescence reading times of less than 60 seconds for 384-well plates and less than 3 minutes in the 1536-well format. Dispensing of cells starts the receptor activation signal within the reader. A cell recirculation function ensures homogeneous cell dispensing, and thus, data quality. Cell stress has been eliminated by optimization of pumps and nozzles. Sensitivity levels allow reliable results to be obtained with one thousand cells per well. Time and cost savings for cell-based GPCR and calcium channel assays are enabled by an easy combination of agonist and antagonist screening.