Aldosterone, blood (0 minute baseline)

This test measures the amount of aldosterone in your blood at a baseline time point, sometimes labeled 0 minutes. Aldosterone is a hormone made by your adrenal glands that helps your body control salt, water, and potassium balance, which influences blood pressure and fluid status.

It is often assessed alongside renin or as part of a series of timed samples to understand how your adrenal system is responding under specific conditions such as posture or salt intake. Your clinician uses this baseline value to compare with other measurements and clinical findings.

Measuring aldosterone can help find the cause of high blood pressure that is difficult to control, low potassium, or symptoms that suggest your body is holding too much salt or water. It is a key test when your clinician is considering primary aldosteronism, a condition where the adrenal glands make too much aldosterone.

The result can also provide clues about adrenal insufficiency or problems with the kidneys or blood flow to the kidneys. Understanding your aldosterone level helps guide next steps, which may include medication adjustments, confirmatory testing, or imaging, depending on your overall health and history.

Your result will be interpreted in the context of how and when the sample was collected, your salt intake, your posture before the draw, and any medicines you take. Different laboratories can use different methods, so your healthcare professional will compare your result to the reference interval used by the testing lab and to your clinical picture.

If your level is higher or lower than expected, your clinician may repeat the test under controlled conditions, review medications that can affect aldosterone, and order related tests such as renin or confirmatory suppression or stimulation tests. In some cases, further evaluation with imaging or specialty referral is considered. Do not change or stop medications without medical guidance.