A New Decade of ME Research: The 11th Invest in ME International ME Conference 2016
Mark Berry presents the first in a series of articles on the 11th Invest in ME International ME Conference in London ...
Discuss the article on the Forums.

Question regarding 'fasting' adrenal blood test...?

Discussion in 'Diagnostic Guidelines and Laboratory Testing' started by SilverRose88, May 13, 2011.

  1. SilverRose88



    I'm not sure if this is the correct place to post this but wondered if someone could shed some light... my doctor has told me he's arranging for a 'fasting' adrenal blood test that he'll do when he comes out to see me next... he wants to do this before upping my Fludrocortione which I've just started for my low BP. I've no idea what this test is as it doesn't sound like the ACTH test?? Does anyone have any idea what test he is on about? My Dad spoke to him so didn't actually go into detail he just repeated to me what he'd said...

    Thanks in advance :)

    Oh and I'm on hydrocortisone which he knows about, won't this effect it?

    Becca x
  2. BEG

    BEG Senior Member

    Southeast US
    Don't know if this will help, Becca. I saw my doc last week for yearly physical. I fasted for the CBC (complete blood count). At the same time, he also tested cortisol, DHEA and DHEAS. Perhaps this is what your doctor will be testing.
  3. jen1177


    I just got a cortisol blood test done today and I fasted just to be safe. I'm pretty sure that eating a meal affects the cortisol levels -- something to do with the adrenals pumping out more cortisol to deal with the increased levels glucose or insulin or something along those lines. That is of course if the adrenals are working properly.

    And, yes, the hydrocortisone you're on will affect the results. But that's OK because your doc is probably checking to see if the dose you are on is right for you, or is too high or too low.

    I think the test your doc is talking about is a simple blood test to check the level of cortisol. If he does another one after you've been on the increased dose of the hydrocortisone for a whoile, it would be to compare it with this one to see a "before and after" picture of what your body is doing with the hydrocortisone you're taking. If there is not much change btwn the before levels and the after levels, then either the dose is too low or it could be a pituitary problem causing your low cortisol problem.
  4. rlc

    rlc Senior Member

    Hi TaintedLuv, The medicine that youre on will affect the results of any further cortisol tests, for some reason all around the world doctors seem to have very little knowledge of how to test for Adrenal insufficiency and are often completely unaware that a normal cortisol result does not rule out Adrenal insufficiency! And that it essential that the test is done at the right time of day, and that other tests have to be done at the same time as well.

    What should be done is explained in this article http://www.suite101.com/content/adrenalinsufficiency-a1543 It says

    When adrenal insufficiency is suspected, blood for an AM cortisol level along with an ACTH level and an aldosterone level is drawn. With a normal range of 9-25, mcg/dl, blood cortisol levels higher than 19 generally rule out the possibility of adrenal insufficiency. Levels lower than 3 suggest adrenal insufficiency, and levels between 3-19 are indeterminate. In primary adrenal insufficiency, the blood ACTH level is high. A low cortisol with a high ACTH is sufficient to diagnose primary adrenal insufficiency; a low ACTH with a low cortisol level is seen in secondary adrenal insufficiency. Further tests can be used to differentiate pituitary from hypothalamic causes in secondary conditions.

    Regardless of the cortisol level, if adrenal insufficiency is highly suspect, an ACTH stimulation test is performed. In this test the patient is given an injection containing cosyntropin, a synthetic form of ACTH. Cortisol levels are tested prior to administering the drug and at 30 and 60 minutes after the ACTH is given. In adrenal insufficiency the rise is blood cortisol levels is negligible. A longer version of the test can be used to determine if abnormal results are due to pituitary or adrenal disease.

    Patients with adrenal insufficiency are also tested for adrenocorticol antibodies (ACA) and antibodies to the hormone 17-hydroxylase. In autoimmune adrenal insufficiency, these antibodies are present with highest levels seen early in the disease course. Imaging studies are used to help evaluate damaged adrenal glands. In autoimmune adrenal insufficiency, the glands are reduced in size.

    Note: Blood levels of cortisol are decreased in hypothyroidism and increased in hyperthyroidism--levels improve when thyroid hormone levels are corrected. Cortisol may also be increased in pregnancy, in emotional stress, various illnesses, and by oral contraceptives, hydrocortisone, and spironolactone. A normal salt diet should be followed for 2-3 days before having blood drawn. Salivary cortisol tests are more accurate when levels are elevated than in conditions in which cortisol is low.

    ACTH levels are decreased by dexamethasone, prednisone, hytdrocortisone, prednisolone, methylprednisolone and megestrol acetate. ACTH levels rise with the use of amphetamines, insulin, levodopa, metoclopromade, and RU 486.
    In shift workers the AM and PM cortisol and ACTH levels will be reversed.

    So its very important not to be taking medications that effect cortisol results, that the test is done early in the morning, around 8 am because cortisol levels decline throughout the day, so the test needs to be done close to when you wake up, if there to give a true indication of what your highest cortisol levels are,

    More information on the Cortisol test can be found here


    Serum ACTH and Serum Aldosterone must be done at the same time otherwise without doing these tests as well, nobody going to be able to work out whats going on, but the reality is a lot of doctors dont know this and dont do them. Im not aware of any literature that says that the cortisol test needs to be done fasting when testing for Adrenal insufficiency.

    More information on the ACTH stimulation test, which will need to be done if there are any doubts about the initial results can be found here

    On this site theres a very good graph that shows how the different results for the likes of cortisol Aldosterone, DHEA etc can be used to tell between Primary, Secondary and Tertiary Adrenal insufficiency http://en.wikipedia.org/wiki/Adrenal_insufficiency
    Hope this helps, like a say a lot of doctors dont know how to test properly for Adrenal Insufficiency so its very important that you do, and can make sure its being done properly!!

    All the best
  5. ukxmrv

    ukxmrv Senior Member

    I had to fast for the "short Synacten" test
  6. August59

    August59 Daughters High School Graduation

    Upstate SC, USA
    It sounds like he is wanting to check present levels to compare to a year ago to see if current dosage is working. Be aware that certain medications can have an effect on ACTH test and possibly giving a false results. It seems that some docs know this and some don't and the biggest culprit interfering with the ACTH stim test are the opiate pain meds.
  7. SilverRose88


    Thank you heaps for your replies!

    Well I had my blood taken this morning, but the doctor rang this evening to say the labs had rang to say my cortisol was extremely low and he says it is highly likely I have addisons?? But wants to get advice from an endo to see where to go from here... the thing is I've been self prescribing hydrocortisone (was on 25mg at one point, I'm on 15mg now, but didn't take it this morning at 8am obviously), so why are my levels still so low? The reason I self prescribe is because I did a 24 hour saliva test which showed I had adrenal fatigue, but now I'm so confused because the cortisol level is obviously still very low even though I'm on 15mg of hydro? What are the chances this is addisons, could this low cortisol be a one off? (Oh I have most addisons symptoms + brown pigmentation on my arms which I've had since being ill for 11 yrs.. no one has ever taken any notice of it tho!).

    Thank you for all of your help so far it's much appreciated :)
  8. Calico13


    Of course your levels would be low if you are self-treating. You did the test before taking your AM dose and the HC you took the night before is out of your system by morning. This is why some Addison's patients, set an alarm about an hour before they get up for the day to take their first dose. That way the cortisol levels begin to rise before they have to get up and be alert for the day.

    You need to tell your doc you were on HC replacement as it completely invalidates the test. Taking any HC means you cannot test for cortisol, ACTH or have a stim test done. None of the results will mean anything unless specifically timed after you take a dose to see if you are absorbing it.

    If cortisol is your problem, then your symptoms should have gone away on HC right? So something else is going on.
  9. SilverRose88


    Actually my doctor is fully aware I'm on HC, as is the endocrinologist who's wanting me to have the short synacthen test. They've said the day before the test to take my first dose before 8AM and then none until the following day, until after the test. And I was better on 25mg of HC (no where near cured) but I am completely bedbound again on 15mg.

See more popular forum discussions.

Share This Page