7th March 2024

A 42-year-old Afro-Caribbean man comes to the clinic complaining of reduced energy, sleepiness and reduced exercise tolerance.

A 42-year-old Afro-Caribbean man comes to the clinic complaining of reduced energy, sleepiness and reduced exercise tolerance. He has a past medical history of type 2 diabetes, which is well controlled on diet and metformin, and hypertension, for which he takes amlodipine. He is a non-smoker and occasionally has a glass of wine with his dinner. He works as a music teacher and finds it difficult to finish a day of teaching without feeling very run down. He does not know his family history as he was adopted. He is investigated as follows:

Which other investigation should be requested at this stage?

Select the SINGLE most appropriate option from the list below. Select ONE option only.