PROBLEM TO BE SOLVED: To stably test the state of a sensor in a short time without providing plural sets of electrodes.SOLUTION: In a testing mode, a response voltage E2 from which a response resulting from glucose can be obtained is applied, the amount of change of a response current &DeltaI is measured at a predetermined sampling interval just after the application of the response voltage E2, and a time T where the amount of change of the response current &DeltaI becomes smaller than a change amount threshold value &DeltaIth is measured. When the computed time T is smaller than a time threshold value Tth preliminarily determined based on the amount of change of the response current of a normal sensor, it is determined that there is a defect present in the external layer membrane. Based on a relationship between the predetermined time T and a defect ratio and a relationship between the defect ratio and a sensitivity normal-error difference to the normal sensor, a correction value for correcting the response current value measured in a measurement mode is computed.COPYRIGHT: (C)2012,JPO&INPIT【課題】複数の電極を設けることなく、短時間で安定してセンサの状態を検査する。【解決手段】検査モードにおいて、ブドウ糖に起因する応答が得られる応答電圧E2を印加し、応答電圧E2印加直後から応答電流の変化量ΔIを所定のサンプリング間隔で計測し、応答電流の変化量ΔIが変化量閾値ΔIthより小さくなる時間Tを計測する。正常なセンサの応答電流の変化量に基づいて予め求めた時間閾値Tthより計測した時間Tが小さい場合には、センサの外層膜に欠陥が生じていると判定する。また、予め定めた時間Tと欠陥割合との関係、及び欠陥割合と正常センサに対する感度正誤差との関係に基づいて、測定モードにおいて測定される応答電流値を補正するための補正値を算出する。【選択図】図8
