Renin/Aldosterone Test

The measurement of renin and aldosterone levels is a hormonal examination that helps evaluate the regulatory mechanisms of blood pressure and fluid balance, as well as identify hormonal abnormalities that can affect the cardiovascular system. This test enables differentiation between primary hyperaldosteronism (Conn’s syndrome) and secondary causes, providing essential information regarding the etiology of hypertension.

Aldosterone, produced by the adrenal cortex, regulates the reabsorption of sodium and the excretion of potassium in the kidneys, thereby determining the circulating fluid volume and blood pressure. Its secretion is stimulated by renin – an enzyme synthesized in the kidneys that activates angiotensin II. When this system functions excessively or inappropriately, it can lead to persistent, treatment-resistant hypertension and hypokalemia.

Indications:

• High blood pressure, especially when combined with low potassium levels;
• Clinical and laboratory suspicion of primary hyperaldosteronism;
• Need to differentiate between primary and secondary adrenal influences on the RAAS (renin-angiotensin-aldosterone system);
• In-depth analysis of hypertension causes in patients with chronic kidney disease, heart failure, or renovascular pathologies.

Procedure for Measuring Aldosterone and Renin Levels:

The patient is asked to arrive at the clinic early in the morning. During the test, the patient remains in a supine (lying down) position in the Day Care Unit.

• The patient must stay in the supine position for at least 4 hours before the blood sample is taken to ensure hormonal level stability;
• After 4 hours in the supine position, the first blood sample is collected;
• The patient is then asked to maintain an upright position (standing or briefly sitting) for an additional 4 hours;
• After this period, a second blood sample is taken to assess hormonal changes in response to the change in posture.

Preparation for the Examination:

• Blood pressure medications: Antihypertensive drugs must be discontinued 4 weeks prior to the test.
• Licorice and licorice-containing products: Avoid licorice or products containing licorice for 2 weeks before the examination.
• Pain relievers and anti-inflammatory medications: Do not use analgesic or anti-inflammatory drugs before the test.