Islet cells are present in the pancreas in your body and include a variety of cells that secrete specific hormones. The beta subtype of cells release insulin which lowers the sugar/glucose levels in the blood. Development of antibodies against islet cells destroys your own cells in the pancreas resulting in Type 1 diabetes due to autoimmune problems. Presence of islet cell antibody in the blood is a risk factor for developing Type 1 diabetes. This test helps to differentiate between Type 1 & Type 2 diabetes.