There is provided a method for the determination of a glucose concentration in a whole blood utilizing a biosensor. A correction of the measured glucose concentration for dilution error introduced by the solid component of blood cells is calculated based on the change in glucose concentration measured before and after significant glucose has diffused from blood cells into the buffer used to dilute the sample. Thus, the need to centrifuge blood samples to obtain a cell-free serum sample for glucose determination is eliminated.

A reagent for assaying glucose, which comprises a first liquid reagent having a pH of 7.5 to 9.5 and containing at least either glucokinase or hexokinase, glucose 6-phosphate dehydrogenase, and adenosine 5'-triphosphate and a second liquid reagent having a pH of 3 to 5 and containing the oxidized form of nicotinamide adenine dinucleotide phosphate. The reagent can be stored as such stably for long in or out of contact with light at normal or low temperatures, so that it can be stored for long in the site of clinical examination and applied to an automatic analyzer without the necessity for dissolution prior to use.

A sensor utilizing a non-leachable or diffusible redox mediator is described. The sensor includes a sample chamber to hold a sample in electrolytic contact with a working electrode, and in at least some instances, the sensor also contains a non-leachable or a diffusible second electron transfer agent. The sensor and/or the methods used produce a sensor signal in response to the analyte that can be distinguished from a background signal caused by the mediator. The invention can be used to determine the concentration of a biomolecule, such as glucose or lactate, in a biological fluid, such as blood or serum, using techniques such as coulometry, amperometry, and potentiometry. An enzyme capable of catalyzing the electrooxidation or electroreduction of the biomolecule is typically provided as a second electron transfer agent.

A sensor utilizing a non-leachable or diffusible redox mediator is described. The sensor includes a sample chamber to hold a sample in electrolytic contact with a working electrode, and in at least some instances, the sensor also contains a non-leachable or a diffusible second electron transfer agent. The sensor and/or the methods used produce a sensor signal in response to the analyte that can be distinguished from a background signal caused by the mediator. The invention can be used to determine the concentration of a biomolecule, such as glucose or lactate, in a biological fluid, such as blood or serum, using techniques such as coulometry, amperometry, and potentiometry. An enzyme capable of catalyzing the electrooxidation or electroreduction of the biomolecule is typically provided as a second electron transfer agent.

An in vivo electrochemical sensor including a working electrode, and an analyte-responsive sensing layer proximate the working electrode. The sensing layer is exposed at an edge of the sensor, wherein the sensor signal is limited, at least in part, by mass transport of analyte to the sensing layer. The sensor is configured and arranged for implantation into the body of a mammal for contact with body fluids of the mammal. The analyte diffuses to the sensing element via the edge of the sensor, thereby restricting mass transport of the analyte to the sensing element. This is because the solution-contacting surface area of the sensor edge is much smaller than an open face of the sensing layer.