Biosensor system, sensor chip, and method of measuring analyte concentration in blood sample

A method of measuring a concentration of an analyte in a blood sample to be evaluated, comprising:

• a step of acquiring Data a related to the concentration of the analyte based on an amount of electric current that flows in the blood sample due to a reaction involving an oxidoreductase with the analyte used as a substrate, and a step of acquiring, from the blood sample, Data b for temperature correction of the Data a,
• wherein the method is carried out using a sensor chip into which the blood sample is introduced, the sensor chip comprising:
• a first measurement part including an electrode A and an electrode B;
• and
• a second measurement part including the electrode A and an electrode C,
• the step of acquiring the Data b includes a step of applying voltage to the pair of electrodes A and C that have been brought into contact with the blood sample and measuring the amount of electric current that flows in the blood sample according to oxidation or reduction of a redox substance other than the analyte, and
• the method comprising a further step of measuring environmental temperature around the blood sample to be evaluated,
• wherein the further step comprises a first temperature measurement step of measuring the environmental temperature before acquisition of the Data a and the Data b and a second temperature measurement step of measuring the environmental temperature after acquisition of the Data a and the Data b, and
• when the temperatures measured by the first temperature measurement step and the second temperature measurement step are indicated as a first temperature and a second temperature, respectively,
• i) when the first temperature and the second temperature satisfy the following relational expression (1):
• a predetermined value of temperature≦|(Second Temperature)−(First Temperature)| (1),
• the method further comprising a step of determining the concentration of the analyte in the blood sample to be evaluated, with the concentration having been corrected according to the temperature of the blood sample based on the Data a and the Data b with reference to a conversion table,
• wherein the conversion table is established using a relationship where the amount of electric current that flows in a blood sample due to the reaction involving the oxidoreductase with the analyte used as a substrate varies in the same manner as the amount of electric current that flows in a blood sample according to oxidation or reduction of a redox substance other than the analyte, when the temperature of the blood sample varies, and
• in the conversion table, Data c, Data d, and the concentration of the analyte in a reference blood sample corresponding to the Data c and the Data d are described, where the Data c is related to the amount of electric current that flows in the reference blood sample due to the reaction involving the oxidoreductase with the analyte used as a substrate and the Data d is related to the amount of electric current that flows in the reference blood sample according to oxidation or reduction of a redox substance other than the analyte, and
• ii) when the first temperature and the second temperature satisfy the following relational expression (2):
• |(Second Temperature)−(First Temperature)|<a predetermined temperature value (2),
• the method further comprising a step of determining the concentration of the analyte in the blood sample to be evaluated, with the concentration having been corrected according to the temperature of the blood sample based on the Data a and data related to the first temperature and/or the second temperature instead of the Data b with reference to another conversion table, and
• the another conversion table has the Data c and Data e for correcting the Data c according to the temperature of a measurement environment.

A biosensor system, comprising:

• a measuring instrument having an operation part;
• and
• a sensor chip that is insertable into and removable from the measuring instrument and into which a blood sample to be evaluated is introduced,
• wherein the sensor chip comprises:
• a measurement part A that acquires Data a, related to a concentration of an analyte in the blood sample based on an amount of electric current that flows in the blood sample due to a reaction involving an oxidoreductase with the analyte used as a substrate;
• and
• a measurement part B that acquires, from the blood sample, Data b, related to an amount of electric current that flows in the blood sample according to oxidation or reduction of a redox substance other than the analyte, which is a reaction in which the oxidoreductase is not involved, for temperature correction of the Data a,
• a conversion table is stored in the operation part,
• a plurality of data is described in the conversion table in such a manner that one converted value based on Data c and Data d, and an concentration of the analyte in a reference blood sample corresponding to the one converted value are related to each other,
• the Data c is related to an amount of electric current that flows in the reference blood sample, whose analyte concentration is known and whose temperature is fixed at one value, due to the reaction in which the oxidoreductase with the analyte in the reference blood sample used as a substrate is involved,
• the Data d is related to an amount of electric current that flows in the reference blood sample according to oxidation or reduction of a redox substance other than the analyte in the reference blood sample, which is a reaction in which the oxidoreductase is not involved, and
• the operation part is programmed to:
• calculate another converted value that is based on the Data a and the Data b and corresponds to the one converted value based on the Data c and the Data d,
• choose the one converted value that coincides or approximates the calculated another converted value,
• read out the concentration of the analyte in the reference blood sample corresponding to the chosen one converted value, and
• determine the concentration of the analyte in the blood sample to be evaluated, with the concentration having been corrected according to a temperature of the blood sample, based on the read concentration of the analyte in the reference blood sample.