A blood test can be used to determine if there is an ongoing autoimmune inflammation underlying diabetes.
Approximately 90% of people who are diagnosed with type 1 diabetes in childhood or at youth have antibodies for insulin, glutamic acid decarboxylase (GAD), Zinc Transporter 8 (ZnT8Ab) and/or tyrosine phosphorylation (IA2).
Approximately 80% of people who are diagnosed with type 1 diabetes as an adult exhibit GAD antibodies. Young adults may also have IA2 and/or ZnT8Ab antibodies without GAD antibodies.
GAD antibody testing is recommended:
If you develop diabetes as an adult but are under 40 years old.
If you are 40 years or older and...
You do not have metabolic syndrome, meaning no significant abdominal obesity, and blood pressure and lipid levels are normal.
Significant weight loss is associated with your diabetes.
You have a family member with type 1 diabetes.