Fewer than half of newly diagnosed children with type 1 diabetes get autoantibody testing

More than half of children newly diagnosed with type 1 diabetes did not receive islet autoantibody testing in the six months before or after their diagnosis, according to a recent analysis from Epic Research.

Islet autoantibodies are proteins that show the immune system is attacking the insulin-producing cells of the pancreas. Testing for them confirms the autoimmune cause of type 1 diabetes and helps separate it from other forms of the disease, according to the analysis.

Researchers, including Kersten Bartelt, RN, Louis Kazaglis, M.D., and others with Epic, studied 68,439 children diagnosed with type 1 diabetes before age 18 between 2017 and 2025. The data came from Cosmos, a dataset of more than 310 million patient records from 2,200 hospitals and more than 50,000 clinics that use Epic’s electronic health record system. Two independent teams, each made up of a clinician and a research scientist, completed the analysis and reached similar conclusions.

Type 1 diabetes is one of the most common chronic diseases in children. An estimated 196,778 people younger than 20 were living with the disease in the U.S. in 2024, according to modeled estimates published in JAMA Network Open.

How many children received autoantibody testing

The analysis looked at the four autoantibodies the American Diabetes Association (ADA) recommends measuring: glutamic acid decarboxylase (GAD65), islet antigen 2 (IA-2), insulin and zinc transporter 8 (ZnT8). It also included islet cell antibodies, an older test.

Overall, 48.8% of children had at least one of these tests in the 12 months surrounding their diagnosis. The other 51.2% were never tested for any of them. Out of the children who were tested, 70.1% had at least one positive result and 44.3% were positive for two or more autoantibodies. The Epic Research authors said that the untested children “represent a meaningful gap in the diagnostic workup.”

The results did vary by test, though. For instance, out of the tests performed for children diagnosed in 2025, GAD65 had the highest positivity rate at 61.7%, followed by ZnT8 at 60.6% and IA-2 at 56.1%. Islet cell antibodies were positive in 31.4% of tests. Insulin autoantibodies were positive in 24.3%.

Another 13.7% of insulin autoantibody tests came back indeterminate, which the authors said might reflect known challenges in standardizing that test. The researchers added that no single test identifies every child with autoimmune diabetes.

Autoantibody testing rates rose from 2017 to 2025

Additionally, it was found that testing before diagnosis stayed rare but grew for all five autoantibodies. The share of children tested for GAD65 before diagnosis nearly doubled, from 2.4% in 2017 to 4.2% in 2025. ZnT8 testing before diagnosis grew from 0.4% to 3.3%.

The authors said rising testing before diagnosis may reflect growing awareness of type 1 diabetes risk screening programs and the availability of therapies for people identified in the early stages of the disease.

Testing after diagnosis was much more common, as GAD65 remained the most frequently ordered test. However, only 46.6% of children diagnosed in 2025 were tested for it after diagnosis, up from 31.2% in 2017. Insulin autoantibody testing rose from 24.9% to 40.4%, and IA-2 testing rose from 22.4% to 36.3%. ZnT8 saw the steepest increase, climbing from 3.3% to 35.1%.

The analysis also had its limits. Tests done outside the health systems that contribute to Cosmos would not be captured, which could downplay true testing rates. However, the authors noted that nearly all children in the study had some lab result after diagnosis. This could suggest that the gap reflects ordering patterns rather than children dropping out of care.

Why confirming autoimmune type 1 diabetes matters for Tzield

Treatment and monitoring differ by diabetes type. Epic Research noted that an estimated 10% to 15% of children clinically diagnosed with type 1 diabetes test negative for all measured autoantibodies. That result can prompt doctors to look for monogenic or other non-autoimmune forms of diabetes.

The ADA’s 2026 Standards of Care call for screening for presymptomatic type 1 diabetes by testing for autoantibodies against insulin, GAD, IA-2 or ZnT8. Under the ADA’s staging system, stage 2 type 1 diabetes is defined by islet autoantibodies, usually more than one, along with abnormal blood sugar levels.

Autoantibody status has taken on more weight as treatment options have expanded. The FDA first approved Tzield (teplizumab) in 2022 to delay the onset of stage 3 type 1 diabetes in adults and children 8 and older with stage 2 disease. In April, the FDA expanded that indication to include children as young as 1 year old, Sanofi announced in a news release.

In June, the agency granted accelerated approval to Tzield to delay the decline of insulin production in children ages 8 through 17 who were recently diagnosed with stage 3 type 1 diabetes. It’s the first FDA-approved treatment for that use. The approval was based on Tzield’s effect on C-peptide, a marker of the body’s own insulin production, and a required postapproval study is underway to confirm clinical benefit. The label carries a boxed warning for serious and life-threatening viral reactivation.

“The FDA recognizes the large unmet need in patients with type 1 diabetes,” Mahtab Niyyati, M.D., acting associate director for therapeutic review in the FDA’s Division of Diabetes, Lipid Disorders and Obesity, said in the Tzield FDA news release.