Indications for Autoimmune Diabetes Mellitus Insulin Antibody Testing

  • Most useful in establishing autoimmune etiology in previously diagnosed type I DM.
  • Order at least two antibody tests; do not order individual antibody tests.
  • For most cases, use Glutamic Acid Decarboxylase Antibody in combination with one or more of the following: IA-2 Antibody, Zinc Transporter 8 Antibody, Islet Cell Cytoplasmic Antibody, and Insulin Antibody.

Type 1 DM
  • Patient should have diagnosed DM:
    • Antibody testing is not useful for the diagnosis of DM.
    • Testing is not recommended for evaluating autoimmune etiology in patients receiving insulin > two weeks, as insulin antibody formation may occur (false-positive test result possible).
  • Most useful in newly diagnosed DM in children <18 years to establish autoimmune etiology.
  • May be useful in difficult adult cases when it is unclear if patient has type 1 or 2 DM.
Type 2 DM
  • No indication for routine evaluation or management.
  • Not recommended for screening family members of patients with type 1 DM (risk prediction) except in research settings.
Limited Use
  • Latent autoimmune DM in adults (LADA): differentiates LADA from type 2 DM.
  • Genetic testing: identifies patients with DM for whom a genetic etiology is suspected (e.g., monogenic DM, maturity-onset diabetes of the young [MODY]). Lack of antibodies suggests a genetic disorder.
  • Gestational diabetes mellitus (GDM):
    • Screen women with history of GDM to identify those at high risk for progression to type 1 DM.
    • No evidence to suggest test results alter outcomes or improve care when compared to intermittent hemoglobin A1c testing.