1st April 2022

A 35-year-old male presents to his GP with a four-week history of shortness of breath

A 35-year-old male presents to his GP with a four-week history of shortness of breath, palpitations and increased frequency of loose bowel movements. Everyone else in his immediate family are well. He is normally fit and well and takes no regular medications. On examination, you find a slightly enlarged goitre and notice that the patient’s skin is generally very warm to touch. On examination of the respiratory and cardiovascular systems, no abnormalities are found. 

Select the SINGLE most likely investigation option from the list below, which will provide a diagnosis. Select ONE option only.