Thyroid UK
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Cortisol and ACTH Test

I'm getting this done. Since I'm nocturnal my doc said to do it in the afternoon, but I wonder if I should either go back to earlier schedule or just get up early and do it then? I have some symptoms of adrenal fatigue such as weight loss, fatigue, diarhhea, nerves/jittery and all the other stuff. I just wonder if I should do the saliva test as well. My doc says it's not accurate. My father said just do that too and pay for it online.

My vitamin D is down to 25 now but calcium is normal at 9.8 and pth is in normal range now too. I did start supplementing again but only at 2000 iu now due to symptoms of back pain and urination/headaches at a higher dose. B12 is still high at over 2000 but the homocystine test was normal.

8 Replies

I think you should get up early and do it then. Your doctor is a bit of a clown, isn't he. Doesn't matter if you're a night owl, your cortisol production still follows the same 24 hour pattern. So, a 9 o'clock serum cortisol test should still be done at 9 o'clock!

As for the saliva test being inaccurate, it's a darn sight more accurate than the serum test, and also lets you see the whole film, rather than just one snap shot. I think your doctor's got a bit confused. Totally out of his depth, I think!

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I can't remember what this docs reasons were for saying that. I don't think it's helpful to say the doc is a clown though?

I will do my best to get up early for the test but I'm worried that I'll have a low Bg then if I don't get enough sleep or a high and that could skew the test maybe. I often go low in the am and sometimes high from the stress and lack of sleep etc.

Do we need to fast for this one?

The saliva test should be easier done at home obviously.

Thanks GG.


In my opinion, a little light humour always helps. But, if you don't appreciate my sense of humour...


I'm all for that- it just didn't come across that way. At that time.


The point is: are you a night owl as your cortisol rhythm is wrong or because you have worked permanent nights for many decades and have adapted? Even that adaptation can ruin your health as human were designed to get up with the dawn and sleep with dusk. You should have the test in the am even if you've had little sleep and the saliva test is helpful, too, to see the pattern. I think the doctor is just trying to avoid an argument about your ability to get up early enough and, as the tests almost always come back "normal" (unless you have full blown Addisons or Cushings), he knows it doesn't really matter when you have it done, as the NHS won't do anything with the results.

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Angel I'm in the US but who knows what they will do. If it is too low or too high I think he will do something such as continue to follow it or do other tests. I have no way of knowing for sure if he was avoiding an argument etc. I'm not sure what you mean by that. All of us are not designed to get up early because I have never been a morning person, even as a child, and yes I'm a night owl... I developed insomnia in my early 20's and had night sweats and I was waking up every hour literally at one point .

I'm even more nocturnal now since I have all these illnesses which affect my sleep patterns and as I age, that is also a common pattern. My brain has never functioned well in the am, one exception is when I'm on vacation I often get up earlier but I still don't function as well. To the point that I can have car accidents etc. and I'm very irritable. Now my bg crashes badly if I get up too early.

I have been that way forever pretty much. Also if I go to sleep before 2 am I wake up at 2-3 am and I don't fall asleep again until 5-7 am usually. That just happened to me 2 nights ago when I had only had 3 hours sleep and got up earlier for me- I fell asleep at 11:30.

A friend told me this is actually a normal pattern, she read a book which discussed how people long ago would sleep from 10-2am, the first sleep, and then get up to do things or lay in bad and read to each other then having the second sleep at 4-5 am or so.

Anyway I wake up very frequently now and have for years, usually in the second sleep phase I can fall back to sleep quickly. I used to fall alseep very easily as a child but I still never felt good in the am ever and I hated getting up early.


i was told by the lab and my Endocrinologist, to do the tests when i normally wake up, late in the day. The cortisol /diurnal rhythm, changes depending on what your schedule is. My Endo accused me of making my own low AM Cortisol, due to my bad sleep wake schedule. The problem is, that i came to her for help, because i couldn't get up to get my son to school, without becoming extremely ill.

here is a research paper from oxford university:

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Thanks Faith... that is odd she would say that.. I would think too it is the other way around, but I often wonder if my crazy schedule is messing me up.. plus It varies.. I'm scared to get up earlier because my bg always crashes if I do that and eat. I still haven't done my tests but I plan to do it soon because I have to get my next endo blood work this week prolly or next week. I will aim for 11 am -12 pm if I can and I think I'm going to do a saliva test too at some point. How were you ill? I have also had weight loss and other things going on and fatigue etc. I have had 2 bad stomach viruses with vomiting and runs which is very rare, vomiting for me is usually an every few years thing.


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