Advice on timing's of blood test required for upcoming Endo appointment please?

[Bertiepuss]

Hello everyone,

My first endo appointment is finally coming up to investigate possible adrenal issues. I was referred in April after a 'grey' area morning cortisol result and very low blood pressure overnight on a 24hr ambulatory test.

I am required to book a blood test before the appointment (tests listed below) so would like to ask for any advice on timings please? They have already stated it must be fasted and before 10am. I know about thyroid testing guidelines.

Wondering if I need to consider menstrual cycle timing - what stage might be best as I am perimenopausal and on HRT? Also, other vitamins/mineral alongside biotin interactions? Anything else - I haven't found anything online about prolactin, IGF-1 or adrenal cortex antibodies.

Thyroid - TSH, fT4, fT3

Hormones - Oestradiol, FSH, LH

FBC and U&E's

Prolactin

IGF-1

Cortisol

Bone profile

Adrenal cortex Ab screen

Background -

I have been regularly testing thyroid hormones myself over the last year approx. every 3-4 months. fT4 and fT3 both hover around 33% through the range with TSH around 2.4-2.8 (0.27-4.2). All testing guidelines adhered to. Antibodies are always within the low normal range. Thyroid ultrasound showed no atrophy or other abnormalities. This supports there is not an issue with the gland itself but possibly a pituitary deficiency could exist or I just naturally have lower thyroid hormones. I have not been diagnosed with anything thyroid related and do not take any thyroid hormones or glandular support.

Ferritin, B12, folate and Vit D all optimised - ferritin for the last the last 6 months, they rest for a lot longer. I have been on HRT for 18 months and feel this is optimised.

[SlowDragon Administrator]

You should have been advised when to do the test

Normally any adrenal test should be early morning

And thyroid early morning anyway

You might want to look at private saliva test too….for your own information

regeneruslabs.com/products/...

portal-app.inspira-regeneru...

[Bertiepuss in reply to SlowDragon]

Hi SlowDragon , all I was advised was before 10am and fasted. What I'm not sure about is whether the female hormone profile should be done at a particular time of the menstrual cycle. I can't get through to anyone at the endo department to ask.

I did a salvia test a few months back - all 5 points were just into the normal range but were very low in range. See my post about it here if interested healthunlocked.com/thyroidu......

[SlowDragon Administrator in reply to Bertiepuss]

so you had blood pressure monitor……very low BP

Have you had a 24 hour heart rate monitor?

Do you wear a fitness watch that records heart rate

[Bertiepuss in reply to SlowDragon]

I had a 24 hour blood pressure monitor that took readings every half hour - that showed episodes of slightly low blood pressure through the day and then very low blood pressure overnight with several readings of 70's/40's.

I haven't had a 24 hour heart rate monitor but I do wear a fitness ring that measures heart rate. I only wear it at night as it bothers me in the day - that shows readings ranging from 56bpm in deep sleep to 85/90bpm in REM.

[JumpJiving]

For cortisol, the test wants to be 8-9am. Although a tiny bit later would be ok, there is the risk that doctors will reject any result taken after 9am (my GP being a case in point).

If you are taking any steroid-based medications, such as asthma inhalers, you should have been advised when the latest is that you can take them prior to the blood draw. Similarly, if you use oral contraceptives, you should have been advised to stop taking them prior to the test. There is also talk of biotin supplementation affecting cortisol tests, but I don't know if that is confirmed yet. You should check on the HRT as well.

If you don't get useful answers from your doctor/nurse, you should get useful advice regarding cortisol test in the Facebook group at facebook.com/groups/1759489...

[Bertiepuss in reply to JumpJiving]

Hi JumpJiving the problem I have is no-one answers the phone at the edno department to be able to ask these questions! What I've found online is that transdermal HRT seems to be ok, so I'm not too concerned about that and I don't take oral contraceptives or asthma meds but thank you for highlighting those 😊 Thanks for the link to the FB group 👍

[JumpJiving in reply to Bertiepuss]

Bertiepuss Another useful reference (although in need of proof-reading as it does contradict itself sometimes), is mft.nhs.uk/app/uploads/2023...

[Bertiepuss in reply to JumpJiving]

Thank you 😊

[humanbean]

Blood samples are taken at 9am for adrenal investigations because doctors assume that cortisol is at its highest at 9am, and that is the information they want to capture - the highest level.

I have always been dubious that everyone's highest cortisol of the day is being produced at 9am, but since nobody would know without 24 hours of repeated testing of cortisol when their peak output is, doctors just make assumptions.

But questions like...

What happens if someone works shifts and has done for years?

What happens when the person has severe insomnia for a long time?

don't get answered.

[JumpJiving in reply to humanbean]

You are correct. It is a recognised problem:

"morning serum cortisol can appear falsely low in individuals with disrupted circadian rhythm (e.g., night shift workers, jet lag, and severe insomnia)"

ref. academic.oup.com/ejendo/art...

This is definitely something my GP is unaware of, and I suspect the average endocrinologist is unaware of.

[Bertiepuss in reply to humanbean]

Hi humanbean Very true, if you don't fit the standard (assumed) lifestyle how would a test like that be accurate. Thankfully I don't have bad insomnia nor work shifts. I did a saliva cortisol test a few months ago and didn't have high levels at any time of the day, all 5 points were very low but still in range, therefore I would assume this means a morning blood cortisol would be reasonably accurate in my case.