The continuous flow sensor delivers a detection limit of 0.23±0.08 mM and sensitivity of 0.118±0.003 mC mM -1 up to 50 mM creatinine, with the concentration dependence showing only a 2.5% deviation from perfect linearity. We attribute the remarkable FIA performance to the high efficiency of in-flow detection with our integrated graphenic electrodes. More specifically, the porous and embedded nature of our laser-pyrolyzed electrodes, together with the fast kinetics of ferrocyanide at the interface (k0 = 0.011±0.003 cm s -1 ), result in overall detection efficiencies of up to 56 % (Fig. ). If we further account for the partial coverage of the WE in the channel, the observed efficiencies reached up to 90 % of the maximum attainable values, meaning that up to 90 % of the redox probes flowing through the WE were successfully detected.