A metered volume microfluidic device can include fluid flow microfluidics. The fluid flow microfluidics can include an inflow channel, a metered volume chamber positioned to receive working fluid from the inflow channel, a metered volume outflow channel positioned to receive and direct a metered volume of the working fluid when discharged from the metered volume chamber, and a capillary check valve. The capillary check valve can allow excess working fluid to exit the metered volume chamber when filling the metered volume chamber via the inflow channel. The capillary check valve can also prevent excess working fluid that has passed there through from being reintroduced into the metered volume chamber when the working fluid is discharged into the metered volume outflow channel.