SAT-608 Analysis of Utilization Patterns of Diabetes Autoantibodies From Over 1 Million Patient Results Across Lifespan From Birth to Over 80 Years

Abstract Disclosure: C. cheng: None. D. Alfego: None. K.Y. Chun: None. Introduction: It is well established that detection and progression of type I diabetes (T1D) can be identified through screening with multiple diabetes autoantibodies. Recommendations from American Diabetes Association (ADA) have specified measurement of additional diabetes autoantibodies including islet tyrosine phosphatase 2 (IA-2) and/or zinc transporter 8 (ZNT8) after testing negative for the anti-glutamic acid decarboxylase (GAD) antibody. Antibodies against insulin (IAA) is another highly considered biomarker for T1D, especially in patients who are exogenous insulin naïve. While studies have reported increasing incidence of T1D in the US, there is lack of data in the evaluation of diabetes autoantibody utilization by clinicians. As a national reference laboratory, our database provides an opportunity to examine the volume, positivity, and clinical utility of diabetes autoantibody testing at a national level. Objective: To examine diabetes autoantibody tests utilization from year 2014 to 2024 in the US. Methods: A retrospective analysis of testing for autoantibodies to GAD, IA-2, ZNT8 and insulin by immunassays as individual tests and collectively in a 4-antibody panel performed at Labcorp® endocrine specialty lab was conducted for 1,088,926 specimens from 2014 to 2024. Comparisons were made for test volume and antibody positivity of pediatric (age<18) and adult patients up to 80 plus years and across genders (male vs female). For clinical utility assessments, ICD-10 codes associated with each individual diabetes autoantibody and as a panel were reviewed. Results: Overall, testing volume has continuously increased annually for each individual diabetes autoantibody and as a panel. Antibody against GAD is the most frequently ordered diabetes autoantibody. With exception of ZNT8 antibody where test positivity largely remained unchanged following year 2014, antibody positivity shows persistent decrease over time with large increases in test volume for GAD, IA-2, and IAA. Pediatric and young adults (age 18-29) make up the largest groups testing positive for all four diabetes autoantibodies, whereas positivity does not differ between males and females. Type 2 diabetes (T2D) is found to be the most frequent clinical entity associated with ordering of individual diabetes autoantibody and the panel by clinicians. Conclusion: Our findings suggest increasing awareness among clinicians in screening for T1D, most commonly through measurement of GAD antibody. Inclusion of additional diabetes autoantibodies should be strongly considered as increased risk for T1D progression has been established in individuals with 2 or more positive autoantibodies. The association of diabetes auto-antibody test orders with T2D is perhaps related to increased awareness and screening for late autoimmune diabetes in adults, which is often misdiagnosed as T2D. Presentation: Saturday, July 12, 2025