A 40 year old lady presents to OPD with weight loss and palpitations is having hea rate of 110/min, BP=130/70mmHg, bilateral proptosis and warm moist skin. Investigations show undetectable TSH and normal free T4. What is the next best step in diagnosis?
High-Yield Explanation
The clinical diagnosis is Grave's disease. Since TSH is undetectable it fuher highlights this diagnosis. Since the question says next best step, we first have to demonstrate diagnosis of thyrotoxicosis with values of Free T3. The algorithm shown below highlights the impoance of measurement of free T3 levels. Measurement of thyroid stimulating antibodies is not routinely performed to diagnose Grave's disease.