investigations to exclude secondary hypertension

Last reviewed 08/2021

Additional investigations to exclude a secondary cause of hypertension might include:

  • serum potassium - hypokalaemia may indicate diuretics, Conn's syndrome, renovascular disease, Cushing's syndrome
  • serum calcium - for hypercalcaemia
  • thyroid function tests
  • 24 hour urinary VMA x 3
  • MSU x 2 - look for cells, casts, protein
  • urinary free cortisol
  • renal ultrasound, IVU, renal arteriography
  • CXR - look for evidence of end-organ damage

Ambulatory blood pressure monitoring provides an accurate profile of blood pressure fluctuations over a 24 hour period and control for the 'white coat effect'. For example, they may show the paroxysmal rise in blood pressure associated with phaeochromocytoma.