Cross-sectional investigation on the accuracy of alternate site glucose testing using the Soft-Sense glucose meter

The aim of this study was to evaluate possible differences in the results of blood glucose testing with the Soft-Sense blood glucose monitoring system (Abbott MediSense, Wiesbaden, Germany; not yet available in Switzerland) using different sites for drawing whole blood samples.

In total, 66 patients participated in the study. Blood glucose measurements were performed with the Soft-Sense device taking capillary blood from the forearm and the fingertip. The results were compared with blood glucose measurements by means of a laboratory reference method using blood from the fingertips.

276 blood glucose data sets could be obtained and were used for the examination of the accuracy of blood glucose measurements at both different sites. Blood glucose results obtained from the arm with Soft-Sense correlated well and were nearly parallel with the results achieved from the fingertip with a laboratory reference method (regression analysis: slope = 0.981; intercept = 0.045 mmol/l (0.819 mg/dl); correlation coefficient r = 0.943). Error grid analysis showed 99.2% of the measurements within clinically acceptable zones A and B. In addition, finger stick measurements done with the Soft-Sense device and the reference method revealed a strong correlation (regression analysis: slope = 0.959; intercept = -0.042 mmol/l (0.748 mg/dl); correlation coefficient r = 0.972). Error grid analysis showed 98.9% of all blood glucose readings within clinically acceptable zones A and B. Mean absolute percent deviations were 9.3+/- 8.1% for the finger tests and 11.2+/- 8.7% for the arm tests. If blood glucose values exceeded 11.1 mmol/l (200 mg/dl), measurements revealed from the forearm were slightly lower than the measurements obtained from the fingertips.

The results indicate that the automated blood glucose monitoring device Soft-Sense provides accurate results independent of the measuring site. As with other alternate site testing devices, nearly painless blood collection at the forearm might help to increase patients readiness to perform more frequent measurements by self blood glucose monitoring, which is a known prerequisite of improved blood glucose control.