This kit is designed to detect and quantitatively measure the amount of cyclic AMP (cAMP) present in cell-based assay systems. A europium (EU) labeled monoclonal anti-cAMP antibody (donor) is paired with a fluorescently labeled cAMP analog (Acceptor), and in the absence of any endogenous cAMP, will produce a time-resolved energy transfer signal at 665 nm when excited at 340 nm. If cAMP accumulates in the well due to the activation of cellular adenylyl cyclase, this cAMP will compete with the acceptor and will inhibit the formation of the labeled Donor/Acceptor complex thereby decreasing the amount of the energy transfer signal produced. The overall drop in signal is inversely proportional to the amount of cAMP accumulated.