USE OF AN ENZYME THERMISTOR FOR SEMICONTINUOUS BLOOD-GLUCOSE MEASUREMENTS

A method to monitor glucose in whole blood is presented. The aim of th e project was to develop a prototype for a bedside monitor system for semi-continuous monitoring of the blood glucose concentration, requiri ng only one calibration. This was made possible by using the special a dvantage of the thermal sensor technique in combination with the adjus tment of flow. The glucose concentration was determined from the diffe rence between the sensor response and an estimated background signal. Using standard addition technique, calibration factors for background and sensitivity were set and remained unchanged during the monitoring. The background signal was 45 +/- 8 mV (mean +/- S.D., n = 8) and the sensitivity was 28 +/- 1 mV/mmol (mean +/- S.D., n = 4). Recovery in w hole blood was 90-98% (mean 94%, n = 12). With an injection interval o f 3 min the precision with the sensor was <3% over more than 100 blood samples. Response time was about 60 s. The calculated glucose values correlated, r = 0.98, with the values obtained with an YSI glucose ana lyser (Yellow Springs Instruments, Yellow Springs, OH, USA), over the range 2-20 mmol/l.