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BH Thyroid +11... when to stop taking vits and iron before I DIY test?

Another quick question, bought my test today and I feel very empowered and a little nervous! Don't want to mess it up when it arrives! I am sure this question has been covered a zillion times but to clarify...

I am know to skip Levo until after finger prick (like with a normal fasting blood test).

When do I hold the following (I have had them all today)

Ferrous fumerate 210mg.

B12, Vit D3, Vit B, Magnesium, K2

Thank you clever people!

11 Replies

dinkyoodle As far as B12 is concerned, you need to be off it for about four months to get a baseline and see what you are holding on to. What you'll get result wise at the moment is basically telling you if the amount you're taking is too much or too little whilst supplementing, from what I understand. Someone else might have a better explanation.

The others, leave off for 24 hours.

I found that leaving off K2 for a few days made my blood flow easier. It is K1 that aids clotting but I believe K2 may have something to do with it in some small way, unless it's just me.


That's interesting about K2. I will bear that in mind when doing next test


It could be just me SD. Worth a try though to see if it helps.

The very first one I did clotted in the tube very quickly. When I did the next one, I decided to leave off D3 and K2 for a few days and it was so much easier. And I get better flow from the side of my middle finger than my ring finger.


I find just a few days without B12 makes my balance worse so I have continued to take it with the ladt result being around 560, which suggests only just sufficient .Why does a base line matter?


Treepie "Why does a base line matter?"

Initially to see if you are low and need to supplement.

If supplementing then to see how much you're holding on to.

But as you have to be off supplements so long (four months) to get a baseline, and as excess B vits are pee'd out, I personally wouldn't stop supplementing for that long. I'd just leave off for a couple of days then see what the result is. If massively over range I'd reduce my maintenance dose, if at the recommended level I'd stay on the same dose, if lower than last time I tested I'd increase my dose.


The only real reason to stop taking vitamin B12 for a few days before a test is if you want to show the results to your doctor. Lots of doctors freak out if they see high vitamin B12 results even though once you are supplementing vitamin B12 NICE guidelines make it clear testing for it in your blood with a "normal" B12 test is useless as like SeasideSusie says it just shows you are supplementing. In addition there is no evidence that high serum vitamin B12 levels are harmful, however for some reason GPs think they are even though they know you are supplementing.

In regards to the vitamin D you can get false positives if you are on a very high dose if you don't leave sufficient time between taking your last supplement and when you take the test.

I was told to do leave some days for iron as well but I can't remember the reason. (I will look it up.)

So in general for all tests leave 3-5 days between taking the supplement and testing.


According to this page : stopthethyroidmadness.com/l...


a) For most of the below, we learned from our more progressive doctors that you’ll need to be off what you are testing for a minimum of 12 hours, i.e. take nothing the morning of the test.

b) 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”.

c) For saliva, we learned to be off any cortisol-containing or cortisol-changing supplement for up to two weeks, “if possible” and in working with your doctor. Some things we may not be able to get off of, though.


Thanks for the comments. I think I will wait and do 5 days without iron before testing. B12 I ran out of so that one I haven't taken for maybe two weeks, sorry I said I'd had them all. I understand that this is still likely to effect results though.


Hi, can i ask where you got the test kit? I have an appt. with my Dr coming up but I'm not confident that he'll agree to NHS testing me. Thx


See Thyroid UK for two companies that provide a sum to the charity if ordered through them. Blue Horizon offers various tests.

The last time I used the finger prick method I could not get enough blood for the test so for an extra sum a kit was provided for a nurse to use at a BMI private hospital.


dashi2208 Blue Horizon make a donation to ThyroidUK for every test carried out for members. Several ways to do it, fingerprick at home, nurse visit at home, through Spire or Nuffield - all listed here



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