A 45-year-old non-obese man labelled type 2 diabetic for two years requires escalating doses of insulin despite modest HbA1c. He has no ketosis, no family history of early diabetes, and BMI 22 kg/m². Which single test best identifies latent autoimmune diabetes in adults?
- A Anti-GAD65 antibody titre ✓
- B Fasting C-peptide level
- C Urinary ketone measurement
- D HbA1c fraction analysis
Correct answer: A. Anti-GAD65 antibody titre
Explanation
LADA is defined phenotypically by adult onset, non-obesity, and rapid progression to insulin requirement, and serologically by presence of pancreatic autoantibodies, of which anti-GAD65 is the most sensitive marker. C-peptide declines late and overlaps with long-standing type 2 diabetes, so it lacks discriminatory power at this stage.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.