Unusually Elevated Serum Insulin Level in a Diabetic Patient during Recombinant Insulin Therapy

ABSTRACT

Herein, we report a case of unusually elevated serum insulin level as a result of increased anti-insulin antibody (IA)-bound insulin after continuous subcutaneous insulin infusion therapy. Detecting free insulin (unbound IAs) levels after polyethylene glycol pre-treatment could be useful to assess functional insulin levels in diabetic patients receiving insulin therapy. The E170 insulin assay can estimate total insulin (bound IAs and free insulin) levels, but it does not measure the levels of exogenous insulin analogues.