Abstract: Apparatus, methods, and systems for detecting alcohol concentrations of an individual, and in particular in vivo alcohol concentrations of an individual. Alcohol sensing compositions include at least one alcohol-responsive active area comprising a concerted enzyme system having at least a first enzyme and second enzyme capable of acting in concert to facilitate the detection of alcohol. At least one of the enzymes in the concerted enzyme system is a ketoreductase.

Abstract: Analyte sensors featuring an enzyme system comprising diaphorase and a NAD-dependent dehydrogenase may be utilized to detect inhibitors of diaphorase, provided that the transfer of electrons to a working electrode is rate-limiting with respect to the diaphorase. Such analyte sensors may comprise a sensor tail comprising at least a first working electrode, a first active area disposed upon a surface of the first working electrode, and an analyte-permeable membrane overcoating at least the first active area. The enzyme system comprises NAD, reduced NAD, or any combination thereof; a NAD-dependent dehydrogenase, such as NAD-dependent glucose dehydrogenase; and diaphorase. Inhibitors of diaphorase that may be detected include, for example, warfarin, dicoumarol, and similar compounds. A second active area may be present to facilitate detection of an analyte differing from the inhibitor of diaphorase.