Bright bioluminescent reagent system for rapid quantitation of luciferase reporter gene expression in transfected cells and high-throughput drug screens. Key Features: High sensitivity and wide detection range. Detection of as little of 2 fg luciferase and as few as 4 cells. Plus, the emitted light is linear over seven orders of magnitude. Compatible with routine laboratory and HTS formats. Assays can be performed in tubes or microplates, on LJL Analyst, Berthold Luminometer, Top-Count, MicroBeta counters, chemiluminescent image plate readers (CLIPR/LeadSeeker) . Assay reagents compatible with all liquid handling systems. Fast and convenient. Homogeneous "mix-and-measure" assay allows detection of luciferase levels within 10 minutes. The optimally combined reagent system allows a single addition step, and simultaneous cell lysis and detection. Robust and amenable to HTS. Z factors of 0.6 to 0.8 are observed in 96-well and 384-well plates. Can be readily automated on HTS liquid handling systems. Method: Luminescence. Samples: Cells etc. Species: All. Procedure: Assay takes 2 min. Kit size: 1000 tests. Detection limit: 2 fg luciferase.