EDTA (must be received within 6 hr of sample collection). Do not send sample on ice.
Imperial College Healthcare NHS Trust
Charing Cross, Hammersmith and St. Mary’s Hospitals
Updated: March 2010
FIRST LINE INVESTIGATION OF PRIMARY HYPERALDOSTERONISM (CASE DETECTION):
It is important to remember that normokalaemic hypertension constitutes the most common presentation of this disease. Therefore, hypokalaemia alone has a low positive predictive value for primary hyperaldosteronism.
Stop beta blockers for 2 weeks prior to the sample, as beta blockers prevent renin release and stop spironolactone 6 weeks before sample.
Other drugs need not be stopped unless further investigations are required (see below)
Supply details of all therapy on request form
Ensure adequate salt intake – NOT loading
Correct severe hypokalaemia (<3.0 mmol/L) first, as a low potassium directly will reduce aldosterone secretion.
Sit patient quietly for at least 10 minutes
1 X EDTA samples (7.5 ml red top)
Send to lab (must be received within 6 hr of sample collection). Do not send sample on ice.
ARR <91: An aldostorone:renin ratio of <91 pmol/mU makes a diagnosis of primary aldosteronism unlikely (Endocrine Society Clinical Practice Guideline 2016).
Hypokalaemia must be corrected prior to sampling as low potassium reduces aldosterone secretion.
Doxazosin, verapamil (slow release) and hydralazine are the only antihypertensive drugs that do not significantly affect the aldosterone:renin ratio.
ARR ≥91: Aldosterone/renin ratio >91 pmol/mU consistent with primary aldosteronism, further follow up advised.
ARR ≥91, but aldosterone < 280 pmol/L: Although aldosterone/renin ratio >91 pmol/mU the absolute aldosterone concentration makes primary aldosteronism unlikely.
Rossi GP et al Prospective evaluation of the saline infusion test for excluding primary hyperaldosteronism due to an aldosterone producing adenoma. Journal of Hypertension 25:1433-1442
Funder JW et al Primary hyperaldosteronism guidelines: Case detection, diagnosis and treatment of patient with primary hyperaldosteronism: An Endocrine Society Clinical Practice Guideline. JCEM Epub ahead of print Jun 13
Referred test to University Hospitals Southampton
Specimen Labelling Procedure