Aldosterone and Renin

This is a blood test to determine if your aldosterone or renin levels are abnormal. It detects hyperaldosteronism (overproduction of aldosterone) or hypoaldosteronism (underproduction of aldosterone). It may be done if your caregiver identifies an electrolyte imbalance or you develop findings of hyperaldosteronism, such as elevated blood pressure, muscle weakness, low potassium, and high bicarbonate.

Aldosterone is a mineral (salt)-retaining steroid that directly regulates the retention of sodium (salt) by the kidney and indirectly regulates the excretion of potassium. It plays an important role in the control of blood volume and blood pressure. Aldosterone is produced by the outer part of the two adrenal glands, located at the top of each kidney. Its production is stimulated by a complex pathway that includes several other "hormones." The most important of these are renin and angiotensin II, produced indirectly by the action of renin. Angiotensin II then regulates production of aldosterone. In normal people, when renin increases (due to low blood flow to the kidneys, low blood pressure, or salt deficiency), aldosterone increases; when renin is low, aldosterone decreases.

SAMPLE COLLECTION

A blood sample is taken by needle from a vein in the arm for measuring a plasma aldosterone and/or renin level. A 24-hour urine collection for aldosterone is preferred by some physicians, since plasma aldosterone levels are variable - they vary by the time of day the samples are collected and whether you are lying down or standing.

The amount of salt in the diet and medications, such as over-the-counter pain relievers of the non-steroid class (such as Motrin and Advil), diuretics (water pills), beta blockers, steroids, angiotensin-converting enzyme (ACE) inhibitors, and oral contraceptives can affect the test results. Many of these drugs are used to treat high blood pressure. Your caregiver will tell you if you should change the amount of sodium (salt) you ingest in your diet, your use of diuretics or other medications, or your exercise routine for aldosterone testing.

Aldosterone levels fall to very low levels with severe illness, so testing should not be done at times when a person is very ill.

NORMAL FINDINGS

Blood

  • Supine: 3-10ng/dL or 0.08-0.30 nmol/L (SI units)

  • Upright: (sitting for at least 2 hours)

  • Female: 5-30 ng/dL or 0.14-.080 nmol/L (SI units)

  • Male: 6-22 ng/dL or 0.17-0.61 nmol/L (SI units)

  • Newborn: 5.60 ng/dL

  • Child, 1 week-1 year: 1-160 ng/dL

  • Child, 1-3 years: 5-60 ng/dL

  • Child, 3-5 year: 5-80 ng/dL

  • Child, 5-7 years: 5-50 ng/dL

  • Child, 7-11 years: 5-50 ng/dL

  • Child/adolescent, 11-15: years: 5-50 ng/dL

Urine

  • 2-26 mcg/24 hour or 6-72 nmol/24 hour (SI units)

Ranges for normal findings may vary among different laboratories and hospitals. You should always check with your doctor after having lab work or other tests done to discuss the meaning of your test results and whether your values are considered within normal limits.

MEANING OF TEST

Your caregiver will go over the test results with you and discuss the importance and meaning of your results, as well as treatment options and the need for additional tests if necessary.

OBTAINING THE TEST RESULTS

It is your responsibility to obtain your test results. Ask the lab or department performing the test when and how you will get your results.