Use

Measurement of renin activity is useful in the differential diagnosis of individuals with hypertension. Renin levels will be elevated in patients with hypertension due to renal artery stenosis (ie, renovascular hypertension). Measurement of renin activity can also be useful in the diagnosis of primary aldosteronism. Patients with secondary aldosteronism tend to have low renin levels. Renin can also be used to assess the adequacy of steroid substitution in patients with adrenal insufficiency. Renin activity will be normal in patients with adequate supplementation and will be elevated when steroid substitution is inadequate.