The disclosure is and includes at least an apparatus, system and method for a flexible heater sensor suitable for association with a fluid bag. The apparatus, system and method may include a conformable substrate on a ply of the fluid bag opposite a printed flexible heater; and a matched function ink set, printed onto at least one substantially planar face of the substrate. The matched function ink set forms: at least one conductive layer capable of receiving current flow from at least one power source; and at least one dielectric layer capable of at least partially insulating and at least partially limiting conductivity of the at least one conductive layer; wherein the matched ink set is matched to preclude detrimental interactions between the printed inks of each of the at least one conductive and dielectric layers, and to preclude detrimental interactions with the conformable substrate; and wherein the at least one conductive layer and the at least one dielectric layer comprise a sensing circuit that senses at least the temperature of fluid within the fluid bag.