How inaccurate is insulin mixing? Patient variability and syringe dead space effect

One hundred diabetics were investigated for the accuracy and reproducibility with which they delivered a mixture of insulins. In contrast with previous reports, 80 patients delivered their total dose with a bias less than 5% from the prescribed dose and 87 with a CV less than 5%. There was little deterioration with age. The proportions of short- and intermediate-acting insulin prescribed were also delivered with commendable skill. In a separate study, syringe dead space was shown to incur a potential financial loss through insulin wastage, as well as affecting the proportions of short- and intermediate-acting insulins delivered.