Role of Antibody Testing in Type 1 Diabetes

Primary Uses of Antibody Testing

The American Diabetes Association recommends standardized islet autoantibody tests for classification of diabetes in adults when there is uncertainty about whether a patient has type 1 or type 2 diabetes 1, 2
Antibody testing helps identify latent autoimmune diabetes in adults (LADA), which affects approximately 5-10% of White adults who present with a type 2 diabetes phenotype but have islet autoantibodies (particularly GADA) 3
Multiple positive autoantibodies strongly indicate autoimmune etiology and predict faster progression to insulin dependence, with a 70% risk of developing type 1 diabetes within 10 years for those with two or more autoantibodies 6

The presence of multiple autoantibodies significantly increases risk of developing type 1 diabetes, with a 15% risk within 10 years for those with a single autoantibody and a 70% risk within 10 years for those with two or more autoantibodies 6, 7
Antibody testing allows staging of type 1 diabetes, including Stage 1: Multiple autoantibodies with normoglycemia (presymptomatic), Stage 2: Autoantibodies with dysglycemia (presymptomatic), and Stage 3: Clinical diabetes with overt hyperglycemia (symptomatic) 2, 5

The American Diabetes Association recommends against routine screening for islet autoantibodies in the general population, but screening may be considered in research settings or as an option for first-degree relatives of individuals with type 1 diabetes 1, 2, 6, 8
The risk of developing type 1 diabetes in first-degree relatives is approximately 5%, which is 15-fold higher than the general population risk 1, 2

For suspected type 1 diabetes without classic presentation, the American Diabetes Association suggests starting with GAD antibody testing, followed by additional antibodies if needed 5
In adults with phenotypic overlap between type 1 and type 2 diabetes, testing for multiple autoantibodies can help differentiate between the two conditions 4, 5

Combining genetic risk scores with autoantibody testing may improve risk prediction, according to the American Diabetes Association 6, 9
Teplizumab has shown promise in delaying clinical onset of type 1 diabetes in high-risk individuals identified through antibody testing 7