The NovaBright™ Phospha-Light™ EXP Assay Kit is a second generation chemiluminescent reporter gene assay for the ultrasensitive detection of secreted placental alkaline phosphatase (SEAP) or the non-secreted placental isozyme PLAP. This assay combines ultrasensitive detection with a dynamic range of 5 orders of magnitude. The assay system uses the high performance alkaline phosphatase substrate, CSPD™ and a proprietary next generation chemiluminescence enhancer and a proprietary buffer system designed to specifically inhibit endogenous non-placental alkaline phosphatase activity to deliver performance surpassing that of prior generations of chemiluminescnt assays and far surpassing colorimetric and fluorescent detection methods. This new kit provides a much simpler procedure than other assays. The assay is homogenious and requires only two solutions both of which are supplied ready-to-use. Prolonged glow light emission kinetics provides a stable light signal for read-time flexibility. The assay signal is measured in a simple luminometer without injectors. SEAP is a reporter protein that is secreted into the cell culture medium and detected by testing aliquots of the medium. Since SEAP is released into the medium, cell lysis is unnecessary. However, the assay also allows the detection placental alkaline phosphase (PLAP) isoenzyme following cell lysis. Sensitive detection of alkaline phosphatase reporter enzyme enables a large number of applications in many areas of life science research, including gene expression, viral function assays, vaccine development, development of viral vectors and gene delivery methods for gene therapy, in vivo gene expression monitoring and novel cellular functional assays. This SEAP assay is one of the easiest and fastest methods for optimizing transfection efficiency. Prior generations of NovaBright™ Secreted Placental Alkaline Phosphatase (SEAP) Enzyme Reporter Gene Chemiluminescent Reporter Gene Detection Kit 2.0 have been used widely for reporter gene assays to measure gene expression in established cell lines and in transfected primary cells, including as a gene knockdown/RNA interference read-out. This assay has been used for a wide variety of viral functional assays, including viral gene expression assays, viral replication, viral fusogenicity, virus neutralization and viral-mediated cell-cell fusion, and viral infectivity . Use of the SEAP reporter protein is very enabling for in vivo reporter gene assays, by assaying serum samples from transgenic, transfected or viral vector-infected animals. The NovaBright™ reporter gene assay system has been used to measure SEAP levels in sera from transgenic or transfected whole animals, including mouse, rat, marmoset, monkey and pig sera, and in chicken egg allantoic fluid. The mouse SEAP protein (mSEAP) has recently been developed for improved SEAP protein stability in transgenic mice, and the NovaBright™ SEAP assay has been used for sensitive detection of mSEAP . In addition to reporter gene (gene expression) applications, the assay system is used to measure SEAP as a functional reporter for receptor-ligand binding assays with a SEAP-ligand chimera, protease-mediated secretion, and for secretion pathway activity. The NovaBright™ assay system has also been used for the cellular measurement of non-placental alkaline phosphatase as a biomarker.