From the Guidelines
For new onset type 1 diabetes mellitus, the recommended antibody workup includes testing for autoantibodies to insulin, glutamic acid decarboxylase (GAD), islet antigen 2 (IA-2), or zinc transporter 8 (ZnT8) as stated in the most recent guidelines 1. This approach is based on the latest standards of care in diabetes, which emphasize the importance of early detection and classification of diabetes to guide treatment decisions and potentially delay disease progression. 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. Key points to consider in the antibody workup for new onset type 1 diabetes mellitus include:
- Testing for autoantibodies to insulin, GAD, IA-2, or ZnT8 at initial diagnosis before starting insulin therapy
- The use of standardized islet autoantibody tests for classification of diabetes in adults with 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
- 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 when multiple islet autoantibodies are identified 1. Overall, the antibody workup is a crucial step in the diagnosis and management of new onset type 1 diabetes mellitus, and should be guided by the most recent and highest quality evidence 1.
From the Research
Antibody Workup for New Onset Type 1 Diabetes Mellitus
- The presence of certain autoantibodies is a key factor in the diagnosis of type 1 diabetes mellitus (T1D) 2, 3, 4.
- Autoantibodies against glutamic acid decarboxylase (GAD), insulinoma antigen-2 (IA-2), insulin (IAA), and zinc transporter 8 (ZnT8) are commonly found in patients with T1D 3, 4.
- GAD autoantibodies are present in the majority of patients with new onset T1D, and are often used as a diagnostic marker 2, 5.
- The presence of multiple autoantibodies is associated with a higher risk of developing T1D, and can be used to predict the disease in relatives of patients with T1D 4.
- Autoantibody levels can fluctuate over time, and transient autoantibody positivity has been reported in adult onset autoimmune diabetes 3.
- The following autoantibodies are commonly tested in the workup for new onset T1D:
- Glutamic acid decarboxylase (GAD) autoantibodies
- Insulinoma antigen-2 (IA-2) autoantibodies
- Insulin (IAA) autoantibodies
- Zinc transporter 8 (ZnT8) autoantibodies
- The presence of these autoantibodies can help distinguish T1D from other forms of diabetes, such as type 2 diabetes and latent autoimmune diabetes in adults (LADA) 3, 6.