Renin and Aldosterone
Definition
Renin is a protein produced by the kidneys that acts as both an enzyme and a hormone; it helps regulate blood pressure by controlling aldosterone production in the adrenal glands. Renin and aldosterone together regulate blood pressure by adjusting the potassium and sodium balance, and they generally rise and fall together; for this reason they are usually ordered together.
Purpose
Distinguishes whether the adrenal glands are producing too much or too little aldosterone. It is especially valuable in diagnosing primary aldosteronism, a condition with high blood pressure that, if untreated, can lead to stroke, heart attack, or kidney failure.
Results
Renin and aldosterone are evaluated together:
| Renin | Aldosterone | What it may suggest |
|---|---|---|
| Low | High | Primary aldosteronism |
| High | Low | Addison disease |
| High | High | Secondary aldosteronism due to heart, liver, or kidney disease |
| Low | Low | Cushing syndrome |
Normal Values
Specific to the laboratory; also varies over the course of the day.
Risks and Limitations
A number of factors can affect the result:
- Medications, birth control pills, blood pressure medications, diuretics
- Salt intake, salt restriction may be required before the test
- Posture and stress, sitting, standing, and stress level change the result
Licorice root (black licorice) must be stopped at least two weeks before the test, it affects results.