Aldosterone-to-renin ratio (ARR)
2 days The aldosterone/renin ratio (ARR/RAR) is a laboratory test used to assess the renin–angiotensin–aldosterone system and to screen for primary hyperaldosteronism, one of the endocrine causes of secondary arterial hypertension.
The test includes measurement of aldosterone and renin levels, followed by calculation of their ratio.
Indications
The test may be recommended in cases of:
- arterial hypertension (especially resistant, severe, or early-onset);
- hypertension associated with hypokalemia (spontaneous or diuretic-induced);
- suspected primary hyperaldosteronism;
- presence of an adrenal incidentaloma;
- family history of early-onset hypertension or hyperaldosteronism;
- increased cardiovascular or renal risk in hypertensive patients.
Procedure
Venous blood sample collection.
Aldosterone and renin are measured in the laboratory, followed by calculation of the ARR/RAR ratio.
Result interpretation
The ARR/RAR is used for screening primary hyperaldosteronism and for evaluating certain forms of secondary hypertension.
The result is not diagnostic on its own and must be interpreted by a physician in a clinical context, taking into account potassium levels, renal function, ongoing treatment, body position, and sampling conditions.
Medical sources:
https://www.endocrine.org/clinical-practice-guidelines/primary-aldosteronism
https://primaryaldosteronism.org/step-1-aldosterone-renin-ratio-arr/
https://pmc.ncbi.nlm.nih.gov/articles/PMC4525911/
https://pmc.ncbi.nlm.nih.gov/articles/PMC5843892/
https://www.sciencedirect.com/topics/medicine-and-dentistry/aldosterone-to-renin-ratio
Preparation:
- blood sample is collected in the morning, after at least 2 hours in an upright position;
- before sampling: 5–15 minutes of rest in a seated position;
- preferably fasting (water is allowed);
- normal salt intake (no low-sodium diet);
- 24–48 hours prior: avoid alcohol, intense physical activity, and stress;
- avoid smoking before sampling;
- inform the physician about all medications (especially antihypertensives, diuretics, hormonal therapies);
- do not stop treatment without medical advice.
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