An aldosterone (ALD) test measures the amount of ALD in your blood. It’s also called a serum aldosterone test. ALD is a hormone made by the adrenal glands. The adrenal glands are found on top of your kidneys and are responsible for producing several important hormones. ALD affects blood pressure and also regulates sodium (salt) and potassium in your blood, among other functions. Too much ALD can contribute to high blood pressure and low potassium levels. It’s known as hyperaldosteronism when your body makes too much ALD. Primary hyperaldosteronism could be caused by an adrenal tumour (usually benign, or noncancerous. These include congestive heart failure, cirrhosis, some kidney diseases (e.g., nephrotic syndrome), excess potassium, low sodium, and toxemia from pregnancy.