From the Guidelines
Individuals with a family history of type 1 diabetes or otherwise known elevated genetic risk should be tested for antibodies to diagnose asymptomatic type 1 diabetes. This recommendation is based on the latest guidelines from the 2025 standards of care in diabetes, which suggest that autoantibody-based screening for presymptomatic type 1 diabetes should be offered to those with a family history of type 1 diabetes or otherwise known elevated genetic risk 1.
Key Points to Consider
- The presence of multiple confirmed islet autoantibodies is a risk factor for clinical diabetes, and testing for dysglycemia may be used to further forecast near-term risk 1.
- Standardized islet autoantibody tests are recommended for classification of diabetes in adults who have phenotypic risk factors that overlap with those for type 1 diabetes, such as younger age at diagnosis, unintentional weight loss, ketoacidosis, or short time to insulin treatment 1.
- The most relevant autoantibodies to test for include autoantibodies to insulin, glutamic acid decarboxylase (GAD), islet antigen 2 (IA-2), or zinc transporter 8 (ZnT8) 1.
Testing Recommendations
- Testing for multiple antibodies increases diagnostic accuracy, as the presence of two or more antibodies strongly predicts progression to clinical diabetes.
- Referral to a specialized center for further evaluation and/or consideration of a clinical trial or approved therapy to potentially delay development of clinical diabetes should be considered when multiple islet autoantibodies are identified 1.
From the Research
Identification of Asymptomatic Type 1 Diabetes
To diagnose asymptomatic type 1 diabetes, certain individuals should be tested for antibodies. The following groups are recommended for testing:
- First-degree relatives of patients with type 1 diabetes, as they are at a higher risk of developing the disease 2, 3
- Individuals with multiple autoantibodies, as they have a higher predictive value of childhood type 1 diabetes 4
- Adults with autoantibody positivity, especially those with high levels of autoantibodies, as they may have a more type 1 diabetes-like phenotype 4
- Patients presenting with type 2 diabetes who are positive for islet cell antibodies (ICA) and/or glutamic acid decarboxylase antibodies (GADAb), as these antibodies can help identify type 1(1/2) diabetes 5
Antibodies to be Tested
The following antibodies should be tested to diagnose asymptomatic type 1 diabetes:
- Islet cell antibodies (ICA) 2, 5
- Glutamic acid decarboxylase antibodies (GADAb) 2, 4, 5
- Insulin autoantibodies (IAA) 2, 4
- IA-2 antibodies (IA-2A) 2, 4
- Zinc Transporter 8 antibodies (ZnT8A) 4
Risk Factors
The following risk factors are associated with the development of type 1 diabetes: