Accuracy and precision of low-dose insulin administration using syringes, pen injectors, and a pump.

We compared the accuracy and precision of low-dose insulin administration using various devices including, for the first time, an insulin pump. We dispensed 1, 2, and 5 unit(s) of soluble insulin (100 units/mL) 15 times each from a NovoPen (3.0 mL), a BD-Mini Pen (1.5 mL), a Humalog Pen (100 units/mL), 30G Precision Sure-Dose Insulin Syringes, 30G BD Ultra-Fine II Short Needle Syringes, and a H-TRON-plus V100 insulin pump. Each dose was weighed on an analytical scale, and the delivered and target doses were compared. Accuracy was defined by the absolute percent difference from the target dose. Precision was defined as the absolute percent difference from the group sample mean. Overall, we found that the pen and pump devices were more accurate, and the pump more precise, than the syringes at the 1- and 2-unit doses. Syringes were dangerously inaccurate, clinically, at the 1-unit dose. The use of pens and syringes with very fine increment markings (1/2 unit) did not improve accuracy or precision. Earlier researchers used multiple individuals to draw and weigh the samples. In an effort to eliminate the potential introduction of significant error; our study used only 2 investigators: 1 to draw up the doses and another to weigh them. The conclusions in our study were similar to prior studies.