Adenosine 3’,5’-cyclic monophosphate (cyclic AMP, cAMP) is an important “second messenger” involved in many physiological processes. BioVision’s cAMP Assay Kit provides a direct competitive immunoassay for sensitive and quantitative determination of cAMP level in biological samples. The kit utilizes recombinant Protein G coated 96-well plate to efficiently anchor cAMP polyclonal antibody on to the plate. cAMP-HRP conjugate directly competes with cAMP from sample binding to the cAMP antibody on the plate. After incubation and washing, the amount of cAMP-HRP bound to the plate can easily be determined by reading HRP activity at OD450 nm. The intensity of OD450 nm is inversely proportional to the concentration of cAMP in samples. In addition, the kit provides a new acetylation procedure to improve detection sensitivity significantly. The kit can detect ~0.1-10 pmol/5 μl (or ~ 0.02-2 μM) cAMP samples.