A radially pressure balanced vane pump includes a housing that defines an inlet port and a discharge port. Under one aspect, an assay device includes a porous, hydrophilic medium; a fluid impervious barrier comprising polymerized photoresist, the barrier substantially permeating the thickness of the porous, hydrophilic medium and defining a boundary of an assay region within the porous, hydrophilic medium; and an assay reagent in the assay region. The bit line made of a metal is manufactured to be integrated with a plug. The attachment structure may include at least one protruding tine, membrane, inflatable balloon, involuted spiral or J-lead that engage one or more sides of the septum.