An optofluidic diagnostic system and methods for rapid analyte detections. The system comprises an optofluidic sensor array, a test plate and an optical detection cartridge. The sensor array supports one or more distinct sensor units, each having a reactor section designed to temporarily enter a series of different kinds of wells in the test plate. One kind of well is a sample reservoir that holds reagent solution to be transferred into the reactor section. Another kind of well is a drainage chamber that removes reagent solution from the reactor section. A third kind of well is a colorant reservoir that holds a colorant reagent transferable into a reactor section. Finally, the sensor unit is transferred to the optical detection cartridge where it is placed into an isolation booth during the optical detection process so that its flat observation face is stationed in a viewing window opposite an optical detector lens.