NAVLE Exam FREE NAVLE Small Animal Internal Medicine Questions and Answers
A 7-year-old intact female Labrador Retriever presents with polyuria, polydipsia, and a history of recurrent urinary tract infections. On physical examination, she is bright, alert, and responsive, with no significant abnormalities noted. Blood work reveals hyperglycemia (350 mg/dL) and glucosuria. Urinalysis shows a specific gravity of 1.010 and bacteriuria. What is the most appropriate initial diagnostic step to differentiate between diabetes mellitus and Cushing's disease as the cause of these signs?