Indications for testing for primary aldosteronism recommended by Hypertension Canada (46) |
Uncontrolled hypertension (> 140/90 mm Hg) despite use of three drugs, one of which is a thiazide/thiazide-like diuretic Hypertension with hypokalemia induced by use of thiazide/thiazide-like diuretics (< 3.0 mmol/L) Spontaneous hypokalemia with hypertension (< 3.5 mmol/L) Hypertension with known adrenal mass
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How to request testing for aldosterone-to-renin ratio (45) |
Patient should stop taking spironolactone or eplerenone for four to six weeks prior to testing. Patient should be instructed to follow a high-salt diet for two days prior to testing. If hypokalemic, the patient should receive oral potassium replacement to restore eukalemia. Plasma levels of aldosterone and renin should be requested, with sample collection occurring while the patient is seated and prior to 10:00 am (fasting is not required).
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Interpretation of aldosterone-to-renin ratio* (44) |
Method for measuring renin | Weak positive result for ARR | Strong positive result for ARR |
Plasma renin activity (ng/mL/h) | 550–750 | > 750 |
Renin concentration (mU/L) | 60–90 | > 90 |
Renin concentration (ng/L) | 100–144 | > 144 |