Problems Interpreting Cortisol Lab Tests in Adrenal Fatigue


Complicating the problem of proper interpretation of laboratory data in adrenal fatigue is the fact that steroid hormones occur in more than one form in your body, but most lab tests measure only one. Cortisol, for example, takes on three forms in your blood: 1) unattached to any other substance (free), 2) loosely bound and, 3) tightly bound to blood proteins. The most common measurement for hormones is the amount of hormone not attached to anything, called the free circulating hormone.

However, this usually represents a meager 1% of the total amount of hormone available. It does not measure the bound hormones, which act as reserves and become free hormones if needed. This reserve can be critical to proper physiological function. For example, very low circulating cortisol levels can be brought to within normal range by the administration of a synthetic cortisol. But people taking synthetic cortisol cannot withstand stress as well as people with naturally normal cortisol levels, even though blood tests for both show normal free circulating cortisol levels.

One reason for this is that although free circulating cortisol levels are increased by taking the synthetic cortisol, levels remain low of tissue bound cortisol that provides reserve stores in cases of emergency (stress). Blood tests can often be deceptive because they do not typically give you the whole picture. Therefore, even though both healthy people and people taking cortisol might show normal free cortisol levels, their response to stress will probably differ considerably. The test results would give a very deceptive picture of “normal” in the case of the person receiving the drug, as it tests only the most superficial layer of cortisol availability.

In adrenal function, the extreme low on a bell curve is Addison’s disease and the extreme high is Cushing’s disease. The other 95% represents an enormous variation in levels of adrenal function that is usually disregarded by lab computers and overlooked by doctors because the scores in this range do not fall into either of the two extreme or “diseased” categories. By default, any scores falling within this range (95%) are considered “normal” The end result of basing laboratory test scores on statistics rather than on signs and symptoms is that many people who have mild to moderately severe adrenal fatigue are never accurately diagnosed; they look “normal” on the tests.

Stress is a factor that significantly affects adrenal hormone levels. Your cortisol level tested after a quiet, relaxing morning will be very different from your cortisol level tested when you are under stress before you arrive at the lab. To obtain a typical value, have your test on a typical morning.

19 thoughts on “Problems Interpreting Cortisol Lab Tests in Adrenal Fatigue

  1. Is it safe to take adrenal glandular extracts for those of us with a history of estrogen positive breast cancers? I know I should avoid DHEA but are there large amounts of sex hormones in the glandualrs?

    1. Hi Jenny,

      The Adrenal Rebuilder is hormone-free and is designed to nourish the adrenal glands and promote natural adrenal health. As always, if you’re unsure, it is best to consult with your healthcare practitioner. Hope this helps – thanks for your question!

  2. My husband recently had his cortisol levels tested by 24 urine test. I am having difficulty interpreting the results. I wonder if anyone could help. They are:
    24 hour normetadre output 1.02 umol
    24 hour urine metadren output 0.67 umol

    He suffers from depression and extreme anxiety.


  3. I have every single symptom of adrenal fatigue given on multiple websites and I’ve had these symptoms for decades. I’ve also been on thyroid replacement since age 12 (Hashimoto’s) and I am now 50. My doctor just ran a morning blood cortisol and ACTH on me and both values were “normal.” The cortisol was 20.3 and the ACTH was 11.8. She then dismissed me. Can I have adrenal fatigue and still have these normal results?

    1. Hi Lynne,

      It is possible, yes – Blood cortisol tests tend to capture a snapshot, so cortisol could be within the normal range at that time. A saliva cortisol test captures a spectrum over a day’s time, so you tend to get an overall picture of cortisol levels. More information on saliva vs. blood cortisol testing can be found in this blog entry as well:

      Hope this helps – thanks for your question, and best of luck!

      Dr. Wilson’s Adrenal Fatigue Team

      1. Thanks so much for the fast reply! I will definitely look at the link you sent. I have a saliva test for cortisol and DHEA-S which I will do on Monday and send back to ZRT. I also did some reading about CBG and wonder if mine may be high due to high estrogen from perimenopause. Evidently high E2 causes the liver to produce more of this binding protein, which ties up the cortisol in the blood so it cannot get into the cells where it is needed. Is there a test for CBG?

        1. No problem, Lynne! There are tests available for CBG, though we don’t have any preferred or recommended facilities for this test. As with any testing, do your research on the testing facility and/or healthcare practitioner analyzing the results. Best of luck!

          Dr. Wilson’s Adrenal Fatigue Team

  4. My moring cortisol test came back almost twice the standard range…I feel I fit all the symptoms of adrenal fatigue…my dr said I cant have it because based on the cortisol test I cant be defiecent

    1. Hi Scott,

      Do you mean your morning cortisol was twice higher than normal? What kind of cortisol test was given? We have more information on adrenal hormone testing in these articles, which you may find helpful.

      Saliva Hormone Testing for Adrenal Fatigue:
      Problems Interpreting Cortisol Lab Tests:

      1. It was a blood test the results were CORTISOL level 29.4 ug/dL blood was drawn at 8am..
        I just did saliva tests shouldnhave results this week. I will read the links you sent thanks.

  5. I recently had pneumonia and had to go to the emergency room…I had a 104.6 fever..they gave me IV antibiotics and a corticosteroid shot…I have alot more energy in the past few weeks since I was sick and was wondering ifmthe antibotics or the corticosteroid has anything to do with it…

      1. Unfortunately my Dr. doesnt buy into the adrenal fatigue and has just lumped me in with all the others just labeled with chronic fatigue….

  6. I had a blood cortisol test at 7am and the results were 33.0 ug/ml. I haven’t had a follow-up appointment with my endocrinologist yet. Are these results concerning?

    1. Hi Amelia,

      Baseline values for a cortisol blood sample taken at 8 in the morning are 6 to 23 micrograms per deciliter (mcg/dL). Did you mean 33 mcg/dl? Morning results of 33.0 ug/ml would be quite low.

  7. HI
    Just did the Saliva test and don’t know how to interpret it: no reference range
    8am: 13nmol/l 12pm:3nmo/l 6pm: less then 3nmol/l and 10pm less then 3nmol
    DHEA s 12.5nmol/
    all my symptoms point to adrenal fatigue/burnout, that’s why I took the test
    Can anyone help with this???

  8. Dear Brandon Derrow
    Thank you very much for the link. I am very disappointed with the lab, range and approx. reading but nonetheless got answers now.

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