A record of dietary salt intake and/or administration of diuretics or vasodilator drugs should be included on the request form. 

Aldosterone, plasma renin concentration and their ratio (ARR) must be interpreted in the context of medications and electrolyte status. For guidance on patient preparation, medications, and result interpretation, click here or contact Chemical Pathologist (03) 9496 5140

For upright requests, collect blood mid-morning (9 - 10 am) from seated patients who have been upright (sitting, standing or walking) for 2 to 4 hours.  

For supine requests, the patient should be lying down for at least 6 hours.

Instructions for: Metropolitan and Regional Collection Centres

• Please collect DEDICATED EDTA (purple) tube. 
• Collect and send to the laboratory at room temperature. 

Cooling of samples below room temperature may cause cryo-activation of Pro-Renin and can lead to falsely elevated results.

Note Aldosterine:Renin ratio (ARR) for the purpose of screening for Primary Hyperaldosteronism: RI <70

An ARR ≥ 70 should be repeated, taking into consideration any interferring medications. If positive again on the second occasion further investigation for Primary Hyperaldosteronism should be considered. It is important to understand that cut-off values may vary even between laboratories using the same testing method, depending on the patient population tested and the sensitivity/specificity desired. In general, lower cut-offs (e.g. around 30) will offer high sensitivity at the expense of specificity while higher cut-offs (e.g. 100) are more specific for primary hyperaldosteronism but may miss milder cases. Clinicians should be aware of the limitations of this cut-off.