SUN-628 Diagnosis of LADA With GAD-65 Autoantibody in a Patient Presenting With Hypoglycemia: A Case Report

Abstract Disclosure: L. Rodriguez: None. P. Remolina: None. N. Shahid: None. H. Maldonado Rivera: None. N. Shaaban: None. Background: Latent Autoimmune Diabetes in Adults (LADA) combines features of type 1 and type 2 diabetes, making diagnosis challenging. Its gradual onset in adults often leads to misdiagnosis as type 2 diabetes, with 4% to 12% of cases initially classified incorrectly (1). Early identification is crucial to prevent poor glycemic control, complications, and ineffective treatment. Clinical Case: A 31-year-old male, initially diagnosed with type 2 diabetes mellitus in 2020, presented to the emergency department with symptomatic hypoglycemia. The patient had an 18-month history of fluctuating hemoglobin A1c levels; during 2023, it increased from 6.2% to 9.4% but dropped to 5.6% in 2024. Additionally, the patient reported experiencing hypoglycemic episodes two to three times per week, including a recent event where his glucose dropped to 40 mg/dL, resulting in loss of consciousness and requiring glucagon (Gvoke) for recovery. The frequency and severity of these episodes led to temporary disability leave, prompting a thorough reevaluation of his treatment plan. Continuous glucose monitoring with the Dexcom G7 over 14 days confirmed frequent hypoglycemic episodes, with glucose levels falling below 70 mg/dL for 8% of the time. Despite discontinuing his long-acting injectable insulin following his last hospitalization and adjusting his oral hypoglycemic regimen—reducing metformin from 1,000 to 500 mg twice daily while continuing sitagliptin (Januvia) at 100 mg once daily—his hypoglycemia persisted, raising suspicion for an alternative diagnosis. Further laboratory evaluation included an autoantibody panel, which revealed negative islet cell antibodies, zinc transporter 8 (ZNT8) antibody levels of <10 U/mL (normal <15 U/mL), and insulin autoantibody levels of <0.04 U/mL (normal <0.04 U/mL). The panel also showed C-peptide level of 7.2 ng/mL (normal range: 1.4-6.8 ng/mL). Additionally, Glutamic Acid Decarboxylase 65 (GAD-65) antibody testing was elevated at 147 IU/mL (normal <5 IU/mL), confirming a diagnosis of LADA. Conclusion: This case supports the routine use and clinical utility of GAD-65 testing in patients with unexplained hypoglycemia or poor response to standard diabetes treatment, as early identification of LADA can lead to more appropriate management strategies and help prevent complications associated with misdiagnosis. Hypoglycemia not only presents immediate dangers to individuals with diabetes, but it also significantly increases the risk of cardiovascular events and mortality. Early detection, careful monitoring, and effective prevention strategies are essential components of diabetes management to reduce these risks and improve long-term health outcomes. References: 1. https://my.clevelandclinic.org/health/diseases/lada-diabetes#:∼:text=How%20rare%20 is%20LADA%20diabetes,adults%20worldwide%20have%20Type%202. Presentation: Sunday, July 13, 2025