Intravenous Insulin: Effect of Binding to the Infusion Set Upon the Dose Administered

Insulin has been known for many years to adsorb to laboratory glassware. This binding is thought to be a nonspecific surface phenomenon which also occurs when small doses of insulin are administered by slow intravenous infusion for therapeutic purposes. While only 8% of the administered insulin is adsorbed to the glass infusion bottle over two hours if 10 units of insulin is added to 500 ml of isotonic saline, when one includes the insulin adsorbed to the tubing, 30% of the insulin activity is lost in two hours.