Aldosterone is a mineralocorticoid hormone that is essential to life because it regulates the amounts of electrolytes in the body. It's secreted by the adrenal cortex, part of the adrenal gland, and is responsible for the reabsorption of sodium into the bloodstream. This hormone also stimulates the excretion of potassium.
Sodium and potassium levels are regulated simultaneously by aldosterone, helping to maintain both blood pressure and bodily fluids. If levels of this hormone fall out of sync, it can cause problems in the body. High levels can cause high blood pressure, muscle cramps and weakness, while low levels may indicate a disease, such as diabetes. Often, aldosterone levels vary between the sexes and may be affected by the amount of sodium in a person’s diet. Women often have significantly higher levels when pregnant.
The hormone renin, which is produced by the kidney, helps to regulate the release of aldosterone, and levels of both hormones are often compared for diagnostic purposes. An aldosterone test may be performed to determine the cause of high or low blood potassium or of certain conditions, such as heart failure or kidney disease.
Most often, aldosterone levels are determined through a blood test. A urine test may be ordered as an alternative, though it is uncommon. People who are being tested for their hormone levels may be asked to stop taking certain medications that could affect the results, including certain hormone supplements and some medications that control high blood pressure. A patient may also be required to eat a specific diet for the two-week period before the test.
Normal laboratory values may vary slightly, and the accuracy of test results may depend on proper preparation as advised by a medical professional. He or she will discuss the results of the test with the patient and explain what the values mean during a follow-up appointment.