Supplements

[Padster7]

Hi all

Does anyone ever stop supplements before blood draw and if so how long for and why.

Thanks

[SmallBlueThing]

The effect of biotin on thyroid tests was brought up about six months ago. Multivitamins/minerals are often criticized for having low levels, but the RDAs were exceeded for most in the one I was taking, and I think its biotin content was 5x RDA. The advice was to stop for three days, and my fT4 dropped from 16 to 12 (9 - 25pmol/L). For the following tests, my TSH has increased above 1.0 miu/L so hasn't triggered a fT4 test. I no longer take a supplement. The increase in TSH accompanied a lower dose following a flare and I suppose subsequent reduced thyroid function last year, but no doubt many will think the lack of a supplement to be a factor.

[fibrolinda]

biotin or anything with biotin in it, stop for 3 days before test as it can give false low TSH and false high t3/4 in some labs testing. Did me with biotin in multi b tablet.

[Clutter]

Padster,

Iron should be stopped 7 days prior to testing ferritin or iron.

Biotin and B Complex vitamins with biotin should be stopped 2-3 days before a thyroid test.

Anything else I would take after the blood draw.

[Padster7]

Thanks everyone I had no idea!! My TSH is usually low so it might stop my endo from thinking I'm over medicated if I stop my supplements for a few days.

[Clutter in reply to Padster7]

Padster7,

Supplements won't affect TSH. If you want TSH to show higher have your blood test between 7.30-8.00am and fast (water only) as TSH drops after eating and drinking.

[SmallBlueThing in reply to Clutter]

High doses of biotin can affect TSH measurement.

endo.confex.com/endo/2016en...

[Clutter in reply to SmallBlueThing]

SmallBlueThing,

Thank you. I thought only FT4 was affected.

[SmallBlueThing in reply to Clutter]

When I checked six or so months ago, I think I absorbed the info that, depending on the type of test used, the measurement for fT4 would be raised with no effect on TSH, or TSH would be lowered, with no effect on fT4. The linked article shows it's more complicated than I thought, with other test results affected.

When I had my flare I mentioned the biotin issue to my GP. At a following appointment when my TSH had risen above 1.0, so there was no fT4 test, I asked if my lowish fT4 when TSH was low might indicate central hypothyroidism as well as the autoimmune thyroiditis, but was told the testing isn't very accurate!

[humanbean in reply to SmallBlueThing]

Wow, thank you for that link, SmallBlueThing !

I wasn't aware that serum B12 testing was affected by biotin as well as TFTs. Notice that the woman they were experimenting with, her serum B12 when taking biotin was >1400 pmol/L. When not taking biotin it was 184 pmol/L.

Does anyone know if the Pernicious Anaemia people are aware of this?

[humanbean in reply to SmallBlueThing]

I've just discovered that the problem is even more widespread :

ddtjournal.com/action/downl...

Quote:

Biotin interference gives falsely high or low results in competitive or immunometric immunoassay respectively (4). It may cause falsely raised thyrotropin receptor antibodies (TRAb) as seen in one of our patients. This could lead to a misdiagnosis of Graves' disease. Biotin also interferes with the measurement of testosterone, oestradiol, dehydroepiandrosterone-sulfate (DHEAS), parathyroid hormone, ferritin and thyroglobulin, testosterone, thyroglobulin, leutinizing hormone (LH), follicle stimulating hormone (FSH), sex hormone binding globulin (SHBG), vitamin B12 and folate (4).

End Quote

[Padster7]

Clutter I always fast and have an early test and TSH always low but only just under range. Why is it necessary to stop supplements, I'm not quite understanding 😞

[helvella Administrator Thyroid UK in reply to Padster7]

High levels of biotin can interfere with some laboratory tests. So if you have been taking large doses in the days before a blood test, the results cannot be trusted.

With iron, taking supplements before a test show as high levels and so do not properly reflect your status.

[humanbean]

This post about biotin discusses the problem and gives some links on the subject :

healthunlocked.com/thyroidu......

[Padster7]

Thanks everyone x

[tanokosohana]

Every supplement has its own prescription, so first of all, you should check that or better speak to your doctor. I've been taking the Thyroid Support formula from prorganiq.com/ for more than six months now, and I didn't have any restriction from my doctor about it. I think it depends on the supplement, and what are the ingredients. There are also different types of tests with different estimations of fT4, so this is also an important factor. I still don't understand why it would be necessary to stop supplements before the blood draw, but I'm not a doctor so I just said my opinion.