Aldosterone Urine Test

Your doctor may order the aldosterone urine test in the following cases:

• As a confirmatory test when the aldosterone blood test points to a condition called hyperaldosteronism (excessive secretion of aldosterone)
• To diagnose the presence of tumours in the adrenal gland
• To detect abnormal functioning of the adrenal glands in a person with high blood pressure and low levels of potassium

Preparations for the aldosterone urine test may vary from one laboratory to another. Your doctor will brief you about the preparation required. The following is a list of instructions commonly given. 

• You will be advised to take a regular amount of salt in your diet for about two weeks before the test. However, avoid salty foods, such as canned vegetables, pickles, potato chips and soy sauce. 
• Let the doctor know if you are on a low-salt diet, as this may interfere with the test results. 
• Some medicines may also interfere with the results of an aldosterone urine test, so inform your doctor if you are taking any prescribed and non-prescribed drugs and supplements. He/she may advise you to stop certain medications about two weeks before the test. These include:
  • Water pills (diuretics)
  • Medications to treat high blood pressure
  • Non-steroidal anti-inflammatory drugs (NSAIDs)
  • Antacids and medications for ulcers
  • Heart medicines
  • Hormones like corticosteroids, oestrogen and progesterone
  • You may be asked you to avoid tea, coffee and sodas on the test day.

Do not stop any medication without consulting your doctor. It is important to give your complete medical history to the doctor for accurate interpretation of the results. If you have any concerns about the test, please speak to your doctor.

This test is conducted on a 24-hour urine sample. The testing facility may provide you with a large container for sample collection and a smaller one to urinate into. The steps listed below are usually followed for collecting the urine sample:

• You will be asked to chose a 24 hour period for urine collection. If possible start at the beginning of the day. 
• Discard the first urine of the day and note the time as the start of your 24-hour urine collection 
• After this, collect all the urine over the next 24 hours. You must collect the urine in the small, clean container and then transfer it to the big container provided by the facility. Strictly avoid touching the inner surface of the big container as it may be lined by a chemical to preserve the urine.
• Keep the container in the refrigerator during the collection period 
• Make sure that you don’t get any hair, toilet paper, faecal matter or blood in the sample. 
• Label the container with your name, the date and time of completion and return the filled container to the facility as soon as possible.

Normal results:

The reference range or normal values for aldosterone in the urine may vary from one laboratory to another. However, in general, the expected range of aldosterone in a 24-hour urine sample is 2-26 micrograms or 6-72 nanomoles. 

Abnormal results:

If the values reported in the test are outside the normal range, it means that there could be an underlying condition causing abnormal release of aldosterone. Higher than normal values could be due to:

• Heart failure
• Kidney disease
• Liver disease
• Tumour in the adrenal gland (Conn’s syndrome)
• High blood pressure in pregnancy (preeclampsia)
• Certain medications that are used for the treatment of hypertension

If your urine aldosterone values are lower than the normal range, it may indicate:

• Addison’s disease (a condition of the adrenal glands where they are unable to produce enough hormones)
• Disorders of the kidney that occur along with diabetes (Read more: Diabetic nephropathy)
• Use of heparin (a medicine used to treat blood clots)

Sometimes, emotional stress and exercise can affect the test results. Therefore, it is best to obtain a detailed analysis of the results from your doctor.

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.