Fig. 5. The KDM-corrected E-AB sensor supports real time, seconds-resolved measurements of plasma irinotecan levels.9,22 (A) In the absence of KDM signals collected at high (120 Hz) and low (10 Hz) frequencies both drift significantly, but because they drift in concert (B) taking their difference (KDM) produces a stable baseline. (C) As expected, control injections of either a saline “blank” or a second chemotherapeutic (5-fluorouracil, which is often co-administered with irinotecan)31,32 do not produce any measurable sensor response.