Table 3. Overview of protocols for drawing blood for ARR screening test for primary aldosteronism: Influence of patient preparation, posture, and sampling conditions.

Recommendations Based on Guidelines:

1. Endocrine Society Guidelines recommend a stringent approach for the most accurate assessment, particularly in high-risk patients.

2. European Society of Hypertension (ESH) allows for more flexibility depending on the clinical setting and patient needs.

Practical consideration and conclusion: While the stringent protocol is ideal and the most accurate results for the ARR require strict adherence to fasting, posture control, and medication adjustments, in real-world practice, a more relaxed protocol may be used for initial screening, with follow-up testing under stricter conditions if necessary.

ACE: angiotensin-converting enzyme; NSAID: nonsteroidal anti-inflammatory drug; ARB: angiotensin II receptor blocker; ARR: aldosterone renin ratio

Procedure Details	Stringent Protocols (Most Accurate)	Moderate Protocols (Pragmatic Approach)	Simple Protocols (Initial Screening)	Remarks
Fasting Requirement:	Overnight (at least 8-10 hours).	Fasting is not strictly required, but light meals low in sodium are encouraged.	No fasting is required.	Food intake can affect aldosterone levels.
Posture Requirement:	-	-	-	-
Resting Period:	The patient rests in a seated or supine position for at least 1-2 hours before blood draw.	The patient rests for 30 minutes in a seated position before blood draw.	The patient’s position can be either seated or lying down, with a brief rest period (5-10 minutes) before the blood draw.	-
Position for Blood Draw:	Blood is drawn after 30 minutes of standing or walking (to standardize upright posture).	Blood is drawn while seated or standing after resting in the same position for 30 minutes.	Blood is drawn without requiring any specific posture adjustments.	This is critical because posture affects aldosterone secretion, which is higher when standing compared to lying down.
Medication Adjustments:	-	-	-	-
ACE inhibitors, ARBs, diuretics, beta-blockers, and NSAIDs:	Should ideally be discontinued for 2-4 weeks before testing.	Some medications may still need to be adjusted, but this protocol allows for more flexibility with essential medications that cannot be stopped.	Limited or no medication adjustments are made. This protocol is often used in situations where medication discontinuation is not feasible.	These medications can affect renin and aldosterone levels.
Spironolactone, eplerenone, and amiloride:	Should be stopped at least 6 weeks before testing.	-	-	Mineralocorticoid receptor antagonists and potassium-sparing diuretics.
Sample Timing:	Morning sampling is preferred.	Allows for any time of the day sampling.	Allows for any time of the day sampling.	Aldosterone levels can exhibit diurnal variation, typically peaking in the morning and decreasing throughout the day.