The present disclosure provides fluidic devices that in some embodiments have passive air control valves and in some instances, high resistance air valve constriction channels, or channel dimensions and compositions that provide effective capillary pressure ratios, that can be used to fill reaction wells and/or manipulate fluids in reaction wells. Also provided are fluidic systems containing fluidic devices adjoined to one another, methods for operating the fluidic devices, and methods for manipulating fluids using the fluidic devices. Methods for use of the fluidic devices in performing immunoassays, nucleic acid detection, other assay systems, including but not limited to point of care applications are also provided.