Blood test to check cortisol

[Jesse-Cat]

I am due for the pre 9 am blood test. Do I take prednisolone prior or do I need to wait till after the blood test?

[SheffieldJane]

Wait until the test is over. As you have surmised it will affect the results. I was told 24 hour gap before the test. I took Prednisalone with me and took it as soon as I could after my test ( check with the nurse). I am surprised that you weren’t told. I felt fine incidentally.

[Jesse-Cat in reply to SheffieldJane]

Thanks. Rheumatologist said to read the forms, I therefore didn't ask but at home noticed there was no additional info. Thanks

[Suffererc in reply to SheffieldJane]

Is that for all blood tests. I am due a test in 2 weeks.

[SheffieldJane in reply to Suffererc]

No just the Adrenal Function blood test.

[SnazzyD]

At the time of mine I was taking my Pred about 5pm (long story) and they said to miss the dose until after the test. The reason is that if you do take it, it may suppress the adrenal glands to an unknown degree and will make the result unreliable. You should have been told. When they take the test they usually ask when you last took it.

[Jesse-Cat in reply to SnazzyD]

Thanks

[PMRpro Ambassador]

As SJ says, 24 hours gap before the blood is taken - and then you can take it straight away aferwards. It isn't too much of a problem when you take it early morning. Take it on time one day, late the next.

Bit more of a pain for those who take it at other times of day like Snazzy and me!!!

[Jesse-Cat in reply to PMRpro]

Thanks

[borednow in reply to PMRpro]

Well, you learn something every day. My GP takes blood samples as and when (they're always OK, thank goodness) and never mentions prednisolone - he's presumably forgotten I'm on it. Pity he isn't

[agingfeminist in reply to borednow]

just to clarify. The advice only relates to blood tests for cortisol. You don't need to stop pred for regular blood tests

[borednow in reply to agingfeminist]

Thank you for clearing that up.

[MrsNails]

After the blood test(s) take it with you & take it when it’s finished, they gave me tea n toast so l took mine then.

[Jesse-Cat in reply to MrsNails]

Thanks

[Rugger]

I'm having the 9am cortisol test in a few weeks. Because I take gastro-resistant pred tablets, I shall be leaving a 36 hour gap before the test. I'll take the dose I would normally take at 9am the day before the test, at 9pm the night before that.....! I don't want to mess up the results of the test by still having some pred in my system. As the others say, I'll have the pred with me to take immediately after the test.

Currently tapering from 4.5mg to 4mg.

[Jesse-Cat in reply to Rugger]

Thanks

[SheffieldJane in reply to Rugger]

Good luck with it Rugger! Is this the blessed light at the end of the tunnel?Are you still on weekly Tocilizumab?

[Rugger in reply to SheffieldJane]

Thanks Jane. I don't dare to think about tunnels / light! On Tocilizumab, I tapered down to 1mg last year and flared, then spent almost 8 months on 5mg. This is "let's try again" territory! The 9am cortisol is just to see what's going on - it was on the low side last year at the same dose.

I'm on weekly Tocilizumab, unless the supply runs out.....! Did you get notification of supply difficulties?

I hope you are managing as well as possible. What a carry on it all is!

[SheffieldJane in reply to Rugger]

No I didn’t get notification of the supply shortages. I have quite a bit in hand. I am prone to infections and therefore stop, now and then.Good luck. I feel fairly exhausted and rotten. Not sure I would recognise a flare. No real pain. On 8 mgs. Trying 10 gaps to see if the side effects lessen

[Nagswoman in reply to Rugger]

I understood that they were using Toz for covid patients.

[Rugger in reply to Nagswoman]

Yes, no doubt that's the reason.

[cool4bob]

I have short Synacthen Test taking one and a quarter hours to one and a half hours from 9.30am on the the 24th, I am currently on 2mg, my appointment letter has note that I should be on 1mg. SheffieldJane should I just delay my dose until after test?

[PMRpro Ambassador in reply to cool4bob]

You absolutely should delay the dose until after the test - you should not have taken any pred in the 24 hours before the test.

[SheffieldJane in reply to cool4bob]

Exactly as PMRPro says - none until after they have done with you.

[cycli]

I am assuming this test only becomes relevant as you low taper and the adrenal glands ability to work is being tested for its functioning. Irrelevant if so in my case but useful to know for the future.

[PMRpro Ambassador in reply to cycli]

To below 5mg you won't get any meaningful result. 5mg is borderline, 3mg is the usual level many endocrinologists set.

[maxgarry in reply to PMRpro]

I am now being asked to have a cortisol test. I am currently taking 20mg Prednisolone daily. Is the test ok at this level? My GP doesn't seem to know.

[PMRpro Ambassador in reply to maxgarry]

Absolutely pointless. At any dose of pred above about 8mg the production of cortisol by the adrenal glands is suppressed by the complex feedback set-up of the HPA axis (hypothalamus, pituitary, adrenal glands).

And frankly - any GP who doesn't know at least that rather basic fact needs some retraining/education!!! I always suspected they slept through physiology lectures ...

[Viv54]

If only i knew !! Keep asking my dr for this test , shes it does not exist !! Far more complicated than people think !! Good Luck with yours .

[PMRpro Ambassador in reply to Viv54]

A good start is to ask for a basal cortisol blood test. That is just a blood test taken about 9am, time isn't absolutely crucial as long as it is in the morning. If the level is below 100 then you have adrenal insufficiency. If it is above 350 nmol/L - you don't. If it is between those reading - you need a synacthen test.

And if she doesn't believe you, here's some reading for her:

ncbi.nlm.nih.gov/pmc/articl...

If she REALLY doesn't think there is such a thing - maybe she needs a) some instruction in how to use a search engine, even google will do and b) some retraining.

[Viv54 in reply to PMRpro]

Yes thats exactly what i asked for , i will go with the information on my next app.Thank you .

[SeasideJohn in reply to PMRpro]

Hi PMRpro,

I'm rather new to all this after only just having had a diagnosis.

Can a Cortisol Blood Test be used to diagnose Adrenal Insufficiency and/or Polymyalgia Rheumatica?

Apologies if it's a daft question.

[PMRpro Ambassador in reply to SeasideJohn]

Not a daft question at all. A study was done and I have put the link up a few times recently and in fact it is the link in my reply just above your question.

Diagnostic performance of basal cortisol level at 0900-1300h in adrenal insufficiency

Worapaka Manosroi

ncbi.nlm.nih.gov/pmc/articl...

"They proposed that if the basal cortisol was >450 nmol/L (16.3 μg/dL), AI could be ruled out, with a negative predictive value of 98.7%. If the basal cortisol level was <100 nmol/L (3.6 μg/dL), AI can be diagnosed with a positive predictive value of 93.2% "

It's probably not widely accepted - but showing the paper to a GP might well elicit the required test to assess is it/isn't it/is it worth a synacthen test.

[SeasideJohn in reply to PMRpro]

Belatedly, Many thanks for your reply..

John

[Nagswoman]

I had to stop taking preds for 3 or 5 days. Can't remember which. Mine was a failure four yeaes ago as, when I got to the surgery at 8.30am, they said they didn't do them there. Well, they had booked me in. I had to go to a different town in the afternoon for it, which is the wrong time of day. Not had once since.

[PMRpro Ambassador in reply to Nagswoman]

You shouldn't have to stop pred for that long - apart from anything else it is downright dangerous for a long term pred patient to stop sudddenly for that long.It risks what you are trying to avoid - an adrenal crisis.