Blood Test for Adrenal Fatigue: What You Should Know Before the Test

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Adrenal Gland Anatomy

In humans, one adrenal gland is situated near the top of each kidney. For this reason, they are sometimes called “kidney hats”. They are triangular in shape and consist of an adrenal cortex (outer portion) and adrenal medulla (inner portion). Both the adrenal cortex and adrenal medulla secrete hormones that are important components for normal body function.

Normal Adrenal Cortex Function

The adrenal cortex, the outermost part of the adrenal gland, is responsible for secreting a variety of hormones. These primary hormones include:

  • Aldosterone – Responsible for preserving and maintaining salt and water balance in the body
  • Cortisol – Responsible for raising blood sugar levels and regulating the body’s response to stress
  • Sex hormones – Responsible for starting and regulating sexual maturation during late childhood and puberty. The amount secreted, however, is much less than that secreted by the testes and ovaries.

Normal Adrenal Medulla Function

The adrenal medulla, the innermost part of the adrenal gland, primarily secretes the “flight or fight” response hormones. They include:

  • Epinephrine – This hormone is sometimes called “adrenalin” and it increases heart rate, contracts blood vessels, and opens air passages.
  • Norepinephrine – This hormone works in conjunction with epinephrine and primarily aids in increasing heart rate, releasing glucose from internal storage sites, and increasing blood flow to the skeletal muscles throughout the body.

Adrenal Fatigue and Selected Symptoms

Adrenal fatigue can be generally described as suboptimal adrenal gland function that usually manifests during stressful life conditions or chronic stress. It is thought that approximately 80% of adults will suffer from adrenal fatigue in their lifetime. Unfortunately, however, most will be either misdiagnosed or under diagnosed. There are many symptoms of adrenal fatigue and adrenal gland malfunction. Here is a list of some of common ones:

  • Feeling constantly tired or fatigued
  • Feeling really tired even after a full night of sleep
  • Difficulty falling or staying asleep
  • Feeling overwhelmed by everyday life situations
  • Salty or sweet food cravings
  • Light sensitivity
  • Difficulty concentrating
  • Slow recovery from illness or injury

Blood Test for Adrenal Fatigue

Cortisol is the adrenal gland-secreted hormone that plays the most significant role in the body’s stress response. Therefore, the typical blood test for adrenal fatigue consists of measuring a person’s cortisol levels four times a day. This test is sensitive to many factors including stress, eating or drinking prior to the test, low blood sugar, and pregnancy. Saliva testing of cortisol and other hormone levels, therefore, are sometimes performed in addition to the blood cortisol tests; in some cases, saliva testing is implemented in lieu of the blood test. In some cases, urine tests and imaging studies (i.e. x-rays, ultrasound computerized tomography (CT) are also used in testing for adrenal fatigue.


Adrenal Gland Disorders. National Institute of Child Health and Human Development.

Adrenal Fatigue Syndrome: Common Symptoms. Jigsaw Health.

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