Response to Jungheim and Koschinsky

Glucose monitoring at the arm

In this issue of Diabetes Care, we read with interest the letter of Jungheim and Koschinsky (1) comparing glucose measurements using blood extracted from the finger versus blood extracted from the forearm. The phenomenon they discuss is not a simple function of measurement technology, but a complex function of circulatory physiology. Our cognizance and study of the phenomenon resulted in the explicit instruction to the users of the TheraSense FreeStyle blood glucose monitoring system to rub the test site before drawing blood. The increased perfusion from rubbing significantly reduces the difference in fingertip and forearm blood glucose measurements (see discussion below). It is significant that Jungheim and Koschinsky did not rub the test site. In addition, their protocol, which involved a glucose tolerance test followed by intravenous insulin, created physiological extremes and influenced the observed differences in study subjects.

An initial TheraSense …