Patent ID: 8097147

Claim:
A method of measuring a quantity of a substrate included in sample liquid, comprising the steps of: providing a biosensor which includes: an insulating board; an electrode section formed on at least a part of the insulating board, the electrode section including a first electrode, a second electrode, and a third electrode; a sample supplying path for supplying the sample liquid to the electrode section; and a reagent layer for reacting with the sample liquid supplied through the sample supplying path, wherein an air hole is provided more downstream than the third electrode for accelerating the flow of the sample liquid; providing a measuring device which includes: a supporting section for detachably supporting the biosensor; and a connecting terminal and a driving power supply for applying a voltage to the electrode section; inserting the biosensor into the supporting section of the measuring device; applying a voltage with the driving power supply to a first group of electrodes including the first electrode and the second electrode; applying a voltage with the driving power supply to a second group of electrodes including the third electrode and one of the first electrode and the second electrode; and determining that the sample liquid is sucked from the air hole by mistake when the electric current from the second group of electrodes exceeds a predetermined threshold before the electric current from the first group of electrodes exceeds the predetermined threshold and when the electric current from the first group of electrodes does not exceed the predetermined threshold within a given lapse of time.