Stop supplements before doing blood tests? - Thyroid UK

Thyroid UK

137,661 members161,433 posts

Stop supplements before doing blood tests?

Kipsy profile image
4 Replies

Hi,

I've ordered thyroid and vitamin (B12, ferritin, fplate and D3) test from medichecks. I've just read on a post today that you should stop iron supplements for a week before you test your ferritin to get any iron out of your system. As I also supplwmwnt D3 and good vitamin B complex daily, does anyone know if I also need to stop these supplements for a week before I do the bloods?

Advice much appreciated. I am new to all this and was diagnosed with Hashis three weeks ago. Having gone gluten free a couple, of weeks ago and started a shedload of supplements, I do feel much better. I'm reluctant to stop the D3 and B vitamins for a week if it's not necessary.

Many thanks in advance.

Written by
Kipsy profile image
Kipsy
To view profiles and participate in discussions please or .
Read more about...
4 Replies
SeasideSusie profile image
SeasideSusieRemembering

Kipsy Bluebug is the iron guru and she always advises to leave off iron supplements for a week, so I would definitely do that.

B Complex - they usually contain Biotin (B7) and biotin can give false readings for thyroid tests so it's best to leave that off for a few days.

D3 - City Assays (Birmingham's NHS City Hospital who do home fingerprick tests for Vit D) say you don't need to stop taking D3 for any length of time, just don't take it on the morning of your test, take it after the blood draw.

By the way, as you're taking D3, are you also taking it's important cofactors, particularly K2-MK7 and magnesium vitamindcouncil.org/about-v...

Kipsy profile image
Kipsy in reply to SeasideSusie

Huge thanks SeasideSusie- such an informative and helpful reply. I will follow that advice about stopping iron and biotin for a week and not taking D3 on the day of testing. Thank you!

Thank you for the link too- I've read it and will get some vitamin K asap and think about boron too. I'm taking magnesium and zinc already. They seem to think vitamin A is best sourced from food although I wonder if that applies to Hashis. It's all getting so expensive!

humanbean profile image
humanbean

I agree about stopping iron, although you can stop it for just 5 days if you want.

STTM has this to say on the subject :

For iron, we learned to be off for 5 days based on information from the Iron Institute, i.e. to see what we are “holding onto”.

Source : stopthethyroidmadness.com/l...

I've tried tracking down the Iron Institute comment STTM refer to for this 5 days off iron, but can't find it. But when I was taking iron myself, I stopped iron because I saw no harm in doing so.

The NHS has this to say on the subject - they don't suggest waiting for 5 days, they just suggest 24 hours and a morning, fasting blood test :

Iron blood test

Iron blood tests are usually taken in the morning before you eat anything. You should also avoid taking iron pills or tablets for 24 hours before your test. Your body absorbs iron very quickly from food or pills, so this can raise your iron levels and affect the test results.

Iron blood tests help diagnose conditions such as iron deficiency anaemia (lack of red blood cells caused by low iron levels).

Source : nhs.uk/chq/Pages/1018.aspx?...

As for stopping B vitamins :

healthunlocked.com/thyroidu......

stopping them for 5 days is a good idea too because of the biotin contained in most B Complex tablets/capsules.

Vitamin D - I've never been sure of the ideal time to stop this.

I decided to make things easy for myself by stopping all my supplements apart from the ones I personally consider absolutely essential for me, for 5 - 7 days before testing. As long as I'm consistent then it works for me.

The ones I consider absolutely essential for me are my 5-HTP (an anti-depressant), magnesium citrate, and my occasional use of potassium supplements. The last two help with muscle spasms and cramps in my legs.

Kipsy profile image
Kipsy in reply to humanbean

Thank you so much for taking the trouble to reply.

You may also like...

Stopping Iron supplements before a TBIC, Ferritin, Iron blood test

wait to get Irons retested? is 6 weeks enough? And do I need to stop Iron supplements including...

Need to stop vitamin D before a vitamin D blood test?

I need to stop taking my vitamin D supplement before a vitamin D blood test? They are also doing a...

Stopping medication before blood tests.

she should stop her medication before doing the blood test. I know levo. has to be stopped 24 hours...

Do I need to stop taking supplements like multi vits etc. before going for blood tests

VitD, B12, Iron, Ferritin. But take a few vitamins so wanted to know if i need to stop these before...

Stopping B12 before blood test?

should stop taking my B12 supplements before I do the test? I also take a tablet with the b12 that...