What are the limitations of the plasma aldosterone/plasma renin activity ratio in the workup of primary aldosteronism?

Updated: Mar 24, 2020
  • Author: Gabriel I Uwaifo, MD; Chief Editor: Romesh Khardori, MD, PhD, FACP  more...
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Answer

Limitations

Limitations in the usefulness of the plasma aldosterone/PRA ration include the following:

  • A major limitation of these tests is the inherent variability of aldosterone secretion due to an intrinsic circadian rhythm

  • Most recommendations suggest performing the test while all antihypertensives that can affect the renin-angiotensin system (RAS) are withheld; this can be difficult to accomplish when severe disease dictates the continuation of some medications to control hypertension (HTN) and hypokalemia during testing.

  • Obtaining the plasma aldosterone/PRA ratio in the setting of chronic angiotensin-converting enzyme (ACE) inhibitor use (ie, >4 wk of use) increases the specificity of the ratio test but reduces the sensitivity

  • Although the usefulness of plasma aldosterone/PRA ratio testing has been well validated in whites and Asians, it has not been validated in other major racial groups.


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