Antibody Binding of Insulin in Diabetic Ketoacidosis

This study investigates the effects of insulin antibody binding on free insulin levels measured in patients with acute diabetic ketoacidosis receiving insulin by constant infusion. In spite of antibody binding ranging from 10 to 90 per cent of the total circulating insulin, the steady state concentrations of free insulin were similar to those observed in individuals on identical infusion rates but without insulin-binding antibodies. However, the levels of free insulin in two patients were substantially lower than expected for the rate of insulin infusion, even though levels of bound insulin were not greatly elevated. An infusion rate of at least 4 U. per hour produced satisfactory rate of fall of plasma glucose, whereas lower dose regimens (2 U. per hour)—producing steady state free insulin concentrations ranging from 28 to 49 mU. per liter in different subjects—were unreliable in controlling the metabolic abnormalities of diabetic ketoacidosis.