Systems and methods for measuring phase flow rates of a multiphase production fluid are provided where a fluidic isolation chamber expands volumetrically in response to fluid pressure from a diverted multiphase production fluid. A pressure-regulating actuator regulates fluid pressure upstream of the fluidic isolation chamber and an upstream fluidic pressure sensor generates an upstream fluidic pressure signal. A fluidic control and analysis unit is configured to communicate with the upstream pressure sensor and the isolation chamber actuator to maintain fluidic pressure upstream of the fluidic isolation chamber as the multiphase production fluid is diverted to the fluidic isolation chamber. The unit generates a total flow rate QTOT as a function of chamber filling time and volumetric expansion and communicates with the fluidic phase detector to generate a relative occupancy indicator I for a target phase of the multiphase production fluid in the fluidic isolation chamber. A flow rate QP for the target phase is generated as a function of the total flow rate QTOT and the relative occupancy indicator I.