PDELight HTS cAMP phosphodiesterase assay kit can be used with all cAMP-dependent phosphodiesterases to produce rapid, quality data suitable for IC₅₀ determinations of screen compounds. The signal is a long lasting luminescence with a half life of greater than 2 hours, which facilitates batch processing. Strong signal and low background allow use in 96, 384 or 1536-well formats with Z’ values generally greater than 0.7. Simple, one-step protocol can be completed in less than 15 minutes. Using existing screening technologies such as IMAP and SPA, the assay does not require the use of radioactive beads, radiolabeled cAMP or specially designed antibodies.