Aldosterone Blood Test

Doctors advise an aldosterone blood test to patients who are at risk of developing hyperaldosteronism or hypoaldosteronism. 

This test may also be ordered:

• To determine aldosterone levels in patients with primary aldosteronism (PA) also addressed as Conn syndrome. PA can result in hypertension (high blood pressure)
• To diagnose secondary aldosteronism (SA) - a type of aldosteronism which is not caused due to adrenal dysfunction. SA is more common than PA and may appear in the following conditions:
  • Liver cirrhosis or kidney disease
  • Pregnancy-related toxaemia
  • Dehydration
• To detect the cause for low levels of potassium in the blood or hypertension (high blood pressure)
• To detect or diagnose suspected conditions such as Addison’s disease or adrenal insufficiency
• If a patient presents with signs and symptoms suggesting overproduction of aldosterone. These include:
  • High blood pressure
  • Weakness of muscles
  • Low levels of potassium
• If a patient presents with signs and symptoms of underproduction of aldosterone such as:
  • Low blood pressure
  • High levels of potassium and low levels of sodium
  • To detect pituitary tumour or causes for low pituitary function

Aldosterone level in the blood is highest in the morning. It varies throughout the day and is often affected by the position of the body, stress levels, and certain food and beverages. 

Stay upright or lie down for 15-30 minutes before the blood is collected. Standing or sitting for more than two hours prior to the test may lead to a rise in blood aldosterone levels.

Additionally, medications such as pain killers, steroids, oral contraceptives, diuretics, beta-blockers and angiotensin-converting enzyme inhibitors can affect the results of this test. Tell your doctor if you are taking any prescription or non- prescription medicines - this includes supplements and herbs. 

Avoid the use of liquorice for at least two weeks before the test as it mimics the properties of aldosterone and can show decreased levels of aldosterone in the test results. 

Aldosterone blood levels reduce during severe illness so this test should not be performed in such cases. Also, pregnancy and exercise can affect the results of the test.

A doctor or lab technician will collect a blood sample from a vein in your arm or the veins in your kidneys or adrenal glands (at specialised labs). The latter specifically helps to detect if one or both the adrenal glands are affected. 

Normal results:

Aldosterone levels in blood vary with change in posture and increasing age. The normal reference range (varies among different laboratories) is as follows:

• In standing or sitting position:

  • Children: 5-80 nanograms per deciliter (ng/dL) or 0.14-2.22 nmol/L
  • Teens: 4-48 ng/dL or 0.11-1.33 nmol/L
  • Adults: 7-30 ng/dL or 0.19-0.83 nmol/L
• In lying position:
  • Children: 3-35 ng/dL or 0.08-0.97 nmol/L
  • Teens: 2-22 ng/dL or 0.06-0.61 nmol/L
  • Adults: 3-16 ng/dL or 0.08-0.44 nmol/L

Abnormal results:

Abnormal results in an aldosterone blood test may signify the following:

High blood aldosterone levels can be due to:

• Dehydration
• Group of rare congenital conditions affecting kidneys (Bartter syndrome) or other kidney diseases
• Liver diseases
• Heart failure
• PA (generally caused by benign adrenal gland nodule)
• A low sodium diet
• Pre-eclampsia (hypertension during pregnancy)
• A tumour in the adrenal glands (Conn syndrome)

Lower than normal blood aldosterone levels can be due to:

• Disorders of the adrenal gland due to lack of aldosterone secretion, including Addison disease
• A high sodium diet
• Certain kidney diseases

Disclaimer: All results must be clinically correlated with the patient’s complaints to make a complete and accurate diagnosis. The above information is provided from a purely educational point of view and is in no way a substitute for medical advice by a qualified doctor.