1st April 2022

A 50-year-old male presents to his GP with a 3-week history of nocturia and polyuria

A 50-year-old male presents to his GP with a 3-week history of nocturia and polyuria. He is normally fit and well with no significant past medical history. His family history includes early-onset hypertension and strokes on his fathers’ side. On examination, his blood pressure is 170/90, compared to his last reading six months ago of 125/80. 

One differential in your mind is Conn’s syndrome.

Select the SINGLE most appropriate screening investigation from the list below to assess whether this patient could have Conn’s syndrome. Select ONE option only.