A novel noninvasive and quasi-continuous method of transcutaneous blood glucose monitoring for use with the human 75-g oral glucose tolerance test (OGTT) was developed. Effused fluid was obtained by applying suction to the skin surface and was labeled suction effusion fluid (SEF). The system consists of a suction apparatus and the glucose sensor system. A vacuum is applied to the patient's skin at 400 mmHg absolute pressure to collect the SEF. The miniature ion sensitive field effect transistor (IS-FET)-based glucose sensor can measure glucose in small SEF quantities. The monitoring system is based on the association between the glucose concentration in the SEF and in the serum. During the 75 g OGTT, the glucose change in the SEF was measured every 10 min. Although a response delay of up to 20 min was observed in the SEF glucose change, it was possible to perform the 75 g OGTT by this noninvasive monitoring method.