A study of forearm versus finger stick glucose monitoring

New glucose monitoring systems are now being launched into the market that offer the patient the option to test from an alternate site (forearm) with less pain. What is not clearly understood by patients and Health Care Providers is whether glucose measurements taken from the forearm are the same as the measurements taken from the finger. The objective of this study was to determine if results from the forearm are the same as results from the finger in normal use by the diabetic patient over a day. In clinical studies conducted in four physician's offices, patients were asked to measure their glucose from their forearm and finger ten times a day for ten days. The patients for this evaluation used the TheraSense FreeStyle glucose monitoring system. A total of 190 patients (of which 30% were type 1 and 70% type 2 diabetics) participated in this study. Patients also concluded their participation in this study with a post study questionnaire. A total of 18,036 data points were collected and used for analysis. Data was separated into four groups: preprandial, 1-h postprandial, 2-h postprandial, and bedtime. In three of the four groups, the mean bias was less than 1 mg/dL or %, whereas the 1-h postprandial group showed a mean bias of -6.02 mg/dL or %. The differences in bias between the 1-h postprandial to the preprandial and the 1-h postprandial to the 2-h postprandial, were statistically significant with a p value of <0.0001. Comparison of bias at 2-h postprandial to the preprandial bias was not statistically significant with a p value of 0.8073, indicating that the 2-h postprandial had an overall mean bias, the same as the preprandial. The 1-h postprandial results indicate that patients who test during this period of time could expect to see significant differences between their forearm and finger measurements. Patients who test during this time period should only test using their finger since this would best represent their true glucose. Patients who would test during periods identified as preprandial and 2-h postprandial could expect to see small differences between their forearm and finger measurements. These differences are also not dependent on the method by which patients use to control their disease.