Blood test due - stopping vitamins before hand - advice please

Hi all,

I am due a blood test following an increase in Levo and prescription of Vit D3 supplements. I know to fast on the morning of the blood test drinking water only and to have the test done early in the morning. I will take my Levo at 1.30 pm as normal after the blood test.

Question - I think I have read to stop all Vit B supplements 5 days before the blood test as to not skew the results. As I also take Vit D3 and MK7, B12 and Magnesium Citrate do any of these supplements need to be stopped?

I am going to ask for my cholesterol to be checked and hope that the blood nurse will do it for me rather than go through the GP (she is excellent but can obviously only work within parameters set by the Practice).

I have had all the other things checked like ferritin (was within range but at bottom of range a few months ago) and will start supplements next week. As a Hashi patient should I be taking Selenium? Should I also be taking Zinc? I have got to send off for another load of supplements from Amazon so would be a good time to order all together.

Thank you for reading - I have received wonderful advice since joining. You lovely people are a lifeline!


8 Replies

  • Lulu23,

    You only need to stop taking biotin or B Complex vitamin containing biotin a day or two prior to your blood tests.

  • Thanks Clutter. And what about Selenium and zinc? Should I be supplementing these too as a Hashi patient?

  • Lulu23,

    Selenium can help thyroid but if it is so bad you are taking Levothyroxine I'm not sure it will do much good. I doubt it will hurt. I'm not aware that Hashi patients need zinc unless they have low zinc or are supplementing magnesium.

  • I'm only taking Magnesium because a few people recommended me to on here. I really don't know if I need too but was reassured that your body would dispel what it didn't need. And selenium I've seen, like Rauscous says below, they take to help with the conversation to T3? But I don't know if this is correct as I'm only 6 months new to this illness.

  • Lulu23,

    I would take zinc as you are supplementing magnesium. Try 200mcg selenium. It won't do any harm.

  • Thanks Clutter

  • I have Hashis and am taking Selenium and zinc (together) because it is supposed to help with the conversion of T4 to T3...I think? It is certainly recommended by many thyroid experts. As far as stopping goes I tend to stop them all for a couple of days just in case but I don't know if it is necessary.

  • Thanks Raucous

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