Measuring blood-glucose levels with a sample drawn from the forearm using the Sof-Tact meter made by Abbott/MediSense will yield the same results as fingerstick testing, say researchers in Massachusetts. The researchers also found that the hematocrit (Hct)—the percentage of whole blood that is composed of red blood cells—was significantly higher in the forearm blood samples than in fingertip blood samples, according to the study published in the February 2002 issue of Diabetes Care.
Researchers at the University of Massachusetts/Memorial Hospital and MediSense Products conducted a study of 50 nonfasting people with diabetes that involved measuring both the subjects’ Hct and their blood-glucose levels. Glucose levels were measured with two instruments: the Sof-Tact blood-glucose system and the HemoCue B-glucose Analyzer. Each subject was tested three times over half an hour. Additional fingerstick tests were taken before and after each session with a laboratory instrument known as the YSI Glucose Analyzer to determine the overall change in glucose levels during the experiment. Hct was measured indirectly, calculated from a hemoglobin result measured by a HemoCue Hemoglobin instrument.
The Hct of the subjects was significantly higher (an average difference of 5.3 percentage points) when measured on the forearm than when measured on the fingertip. Blood-glucose levels were essentially the same—”no significant glucose difference was observed,” the researchers noted—when measured on the forearm and the fingertip, regardless of the type of testing method used.
Clinical adviser’s note: The Sof-Tact blood-glucose meter by Abbott/MediSense is FDA-approved for use with capillary blood samples from the base of the thumb, the forearm and the upper arm.