AKT-1680

AKT-1680

A 48-year-old woman presents to the clinic for follow-up. She reports feeling increasingly fatigued and overwhelmed with caring for her grandchild. Additionally, she has noticed a hoarse voice and persistent tiredness. She has no significant medical history and has never smoked. She has also been experiencing constipation and has started taking daily senna. On examination, her blood pressure is 115/75 mmHg, pulse is 55 and regular, and BMI is 29 kg/m2. She has a smooth, non-tender goiter. Laboratory results show Hb 118 g/L (115-165), WCC 8.0 ×109/L (4.5-10), PLT 180 ×109/L (150-450), Na 131 mmol/L (135-145), K 4.3 mmol/L (3.5-5.5), and Cr 99 µmol/L (70-110). What test or investigation would be most helpful in clarifying the diagnosis?