​Islet antigen-2(IA-2),pre Islet antigen (IA-2), previously known also as ICA-512, is a major target of islet cell autoantibodies. Autoantibodies to IA-2 are present in up to 80% of children and adolescents at diagnosis of type 1 diabetes. Testing for IA-2A complements GAD measurement, since more than 90% of children have antibodies to at least one of these proteins at diabetes onset. IA-2 generally develops later in the process leading to type 1 diabetes and is therefore associated with more rapid progression. These antibodies do not persist as long following diagnosis as GAD and are less common in patients who are diagnosed with type 1 diabetes over the age of 30 years. They are therefore less useful than GAD for characterising diabetes in longer term older patients.

Tested alongside Anti-GAD and Anti-ZnT8.