Aldosterone/Renin ratio (EDTA plasma, frozen (ep))

Patients must stop taking the following antihypertensive agents before the ARR is determined:

• Spironolactone, eplerenone, drospirenone, amiloride, triamterene: at least 4 weeks prior to blood sampling.
• Beta-blockers, AT2 antagonists, loop diuretics, central alpha-2-receptor-Agonists (Clonidine, alpha-Methyl-Dopa), ACE-Inhibitors, Renin Inhibitors, Calcium Antagonists (DHP-Type): at least 2 weeks prior to blood sampling.
• Thiazide diuretics, Calcium antagonists (i.e. verapamil slow release) and alphareceptor blockers (e.g. Doxazosin) do not significantly interfere with diagnosis

Blood sampling (EDTA blood) in seated patients in the morning (8 - 10 am) after a resting period of 15 minutes while seated. Before that, the patient should have been awake for at least 2 hours in an upright position (sitting, standing or walking). As hypokaliaemia leads to false-positive results, it may be necessary to balance it beforehand through potassium substitution. Sodium should not be restricted in the period before blood sampling (sufficient NaCl). EDTA blood (approx.. 3 ml) should be centrifuged after sampling; supernatant EDTA plasma is transferred into a new tube which is labelled accordingly, frozen and dispatched frozen. Caution! Do not store EDTA plasma at 2 - 8 °C, do not cool sample before freezing, but quickly process at room temperature. Cryoactivation may lead to a production of active renin from prorenin (10 times higher plasma concentration than renin) and thus result in false high renin values.
Further inf

For the following groups of patients an optimised PH screening (primary hyperaldosteronism) with additional determination of the aldosterone/renin ratio (ARR) is recommended:

• sustained blood pressure (BP) above 150/100 mm Hg on each of three measurements obtained on different days
• hypertension (BP > 140/90 mm Hg) resistant to three conventional antihypertensive drugs (including a diuretic)
• controlled BP (< 140/90 mm Hg) on four or more antihypertensive drugs
• hypertension and spontaneous or diuretic induced hypokalemia
• hypertension and adrenal incidentaloma
• hypertension and sleep apnea
• hypertension and a family history of early onset hypertension or cerebrovascular accident at a young age (< 40 years)
• all hypertensive first-degree relatives of patients with PH

With an ARR > 19 in more…