How is primary hyperaldosteronism detected?

Updated: Feb 22, 2019
  • Author: Matthew R Alexander, MD, PhD; Chief Editor: Eric H Yang, MD  more...
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Measurement of the ratio of aldosterone to plasma renin activity (PRA) is performed to detect evidence of primary hyperaldosteronism. A ratio of more than 20-30 is suggestive of this condition. Most antihypertensive medications can falsely raise or lower this ratio; thus, an appropriate washout period is necessary to obtain an accurate aldosterone-renin ratio.

As mentioned above, less than half of patients with PA have hypokalemia. However, an underlying secondary cause of hyperaldosteronism should be strongly suspected in patients with unprovoked hypokalemia or who exhibit an exaggerated hypokalemic response to a thiazide. It is important to note that aldosterone levels can be falsely low in the presence of hypokalemia. Hypokalemia and metabolic alkalosis are relatively late manifestations of primary hyperaldosteronism.

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