V vs SHE with the sensors exposed to air were close to those measured under inert atmosphere for both lactate and creatinine. In contrast, for both sensors, the catalytic currents were about 50% lower in absence of the O2-scavenger. This demonstrates the potential for interference-free lactate and creatinine sensing in point-of-care settings even at low substrate concentrations. ) of GCE modified with Os-complex-modified polymer (40wt%) lactate oxidase (50wt%) and PEGDGE (10wt%) at a total loading of 500 μg cm -2 in buffer (1mL) containing CAT, and AOx (pink trace), upon addition of lactate (1 mM, red trace) and upon addition of paraformaldehyde (blue trace). CV (2 mV s -1 ) in buffer (5 mL) containing lactate (1 mM) under inert atmosphere.