Most appropriate test to screen for hyperaldosteronism

What is the most appropriate test to screen for hyperaldosteronism?

After total body potassium stores have been repleted, the ratio of plasma aldosterone to renin measured in (optimally, untreated) patients in the seated position at 8 am is the most widely recommended test. A plasma aldosterone/renin activity ratio >20 ng/dL per ng/mL per hour and the plasma aldosterone level >15 ng/dL is a positive screen for primary hyperaldosteronism. Potential confounders of the test are listed below.

Potential Confounders of the Aldosterone-Renin Ratio

Decrease ARR (higher likelihood of a false-negative test)

• Diuretics

• Angiotensin-converting enzyme inhibitors

• Angiotensin receptor antagonists

• Dihydropyridine calcium antagonists (smaller effect)

• Hypokalemia

• Pregnancy

• Renovascular hypertension

• Hypertensive emergency (formerly, “malignant hypertension”)

Increase ARR (higher likelihood of a false-positive test)

• Beta-adrenergic antagonists

• Alpha-1 adrenergic agonists

• Nonsteroidal antiinflammatory drugs

• High-potassium diet (or “potassium loading”)

• Older age

• Chronic kidney disease

• Pseudohypoaldosteronism, type 2

Changes in dietary sodium and potassium consumption can also affect the ARR, but the magnitude and direction of the changes depend on many other factors.

ARR , Aldosterone-renin ratio.