Cortisol question

[Salphy]

Sorry if this has been asked before but my endo asked me to get cortisol tested at next test.

I asked if it had to be blood as I know they do saliva but he told me not to bother with them and get blood test between 8am-10am fasted with no meds.

What will the blood test tell me?

I rang medichecks before to see if I can get it tested on yesterday's sample and they are going to put the request in.

But I forgot I did the test about 7:45am. Will it make a difference?

Also he's just increased my t4. Will it make a difference if I get it tested now as opposed to with my follow up bloods in 4 weeks?

Thanks

[humanbean]

Why have you been asked to arrange your own serum cortisol test?

[Salphy in reply to humanbean]

I see him privately x

[humanbean in reply to Salphy]

If you arrange a serum cortisol test (i.e. cortisol level in blood) it should give the doctor an indication of how high your cortisol is at the time of day it is generally expected to be at its highest. Cortisol is generally at its highest at roughly 9am, although body clocks do differ. If you work shifts or you suffer pronounced insomnia and sleep all day then your highest cortisol level might occur at some time other than 9am.

If you look at this rough graph you'll see what I mean :

data.integrativepro.com/ima...

It shows cortisol level changing over 24 hours.

This is the kind of test your endo is expecting you to do, I think :

medichecks.com/cortisol-tes...

You must have read posts about people being tested for Total T4 and Free T4, and Free T4 being more accurate.

The same issue arises with cortisol... Cortisol in blood can be thought of as Total Cortisol, whereas cortisol level in saliva is like Free Cortisol, although those terms aren't used, as far as I'm aware. Free Cortisol would give a better idea of what cortisol is available for immediate use by the body.

But, endos expect people to get cortisol tested in blood, so there isn't much you can do.

If you want to know anything about the testing procedures, timing, and interpretation of results used by endo departments then you really need to save this link :

imperialendo.co.uk/Bible201...

Good luck.

[Salphy in reply to humanbean]

Thank you

So for arguments sake to keep him happy. Do you think 15 minutes early will really matter?

[humanbean in reply to Salphy]

No, I think that should be close enough.

The doctor has said :

get blood test between 8am-10am fasted with no meds.

So 15 minutes one way or the other isn't going to make a massive difference.

[Salphy in reply to humanbean]

Saves me having to do another blood test if they can do it off the sample yesterday.

I have a really bad phobia. Managed to avoid venous samples so far. Really gutted I've got to get rt3

[greygoose in reply to Salphy]

If I were you - although I have to admit I'm rather stroppy - before getting the rT3 done, I would ask him why he wants it done. What is he going to do if the result comes back high? How is he going to know what the problem is - because there are so many things that can cause high rT3. If he says it's to see if there's a conversion problem, tell him he doesn't need an rT3 test for that. He can easily see it by comparing the FT4 with the FT3. And, if the FT4 is at the top of the range, the rT3 is going to come back high. So, knowing that, what's the point of doing the test?

[Hidden]

I'm surprised he's asked you to fast for an am cortisol blood test. Blood tests are more accurate to detect high levels of cortisol, as long as the blood is taken around 8-9am that is fine. If he is suspecting low levels of cortisol then saliva tests are not accurate enough to pick it up.

[Salphy in reply to Hidden]

He asked me to fast for that and a full thyroid panel. I don't know which he meant the fasting was for.

I'm not sure what he's suspecting he didn't really say. It's just to look into why I'm still tired when my bloods look ok x