Download Aldosterone-Renin Ratio (ARR)

Aldosterone-Renin Ratio (ARR)
Clinical Applications:
In screening hypertensive patients for the presence of possible primary aldosteronism.
Patient Preparation:
The test is best done in the ambulant state between 0800-1000hrs, preferably in the absence
of drugs affecting the renin – aldosterone axis. Preferred drugs (in patients unable to stop
hypotensive therapy) include alphablockers (eg doxazosin, prazosin) or calcium channel
blockers. Other hypotensives (β-blockers, ACE inhibitors or angiotensin II blockers,
diuretics) may affect results (see “Interpretation”). Note that the use of spironolactone or high
dose amiloride (>10 mg daily) within 6 weeks of testing will invalidate the test.
Plasma sodium, potassium and creatinine should be measured along with ARR.
Sample Aliquot Requirements:
Request both Aldosterone and Renin assay.
Test Details:
Reference interval for aldo/renin ratio:
pmol L
nmol L hr
pmol L
Abnormal  1000
nmol L hr
Suspicious  800
Interpretation:
Aldosterone-Renin ratio values exceeding 1000 strongly support the presence of primary
aldosteronism provided plasma aldosterone exceeds 400pmol/L and the patient does not have
chronic renal failure. Patients with hypokalaemia, or receiving ACE inhibitors, Ang II
blockers, diuretics may have false negative results, requiring repeat tests when eukalaemic or
after appropriate change in drug therapy.
NB: Definitive testing (eg saline suppression test, urine aldosterone secretion during high
sodium intake) is usually required to confirm the presence of primary aldosteronism.