Blood work - I forgot to stop my B complex vitamin...

[Recon]

Hi all,

I just got a series of TSH, FT4 and FT3 for my endo appointment in a week. I followed the guidelines for my T4 and T3 (24hr/12hr respectively)... but I completely spaced the fact that I am taking the Thorne Basic B and a B12 supplement daily.

What will this do to my results??

Argh!

Thanks!

[PurpleNails Administrator]

It may do absolutely nothing.

It’s just a precaution as it’s known that some tests use biotin in the testing process and it’s a possibility it can falsely skew the results. Unfortunately it can be estimated or re-calculated as the error margin is an unknown.

It’s usually for very high doses over the 5000mg (*mcg, supplements says ug & I’m easily confused) standard maximum daily supplement which is more likely to create an issue.

Complexes have lower levels eg 400ug or mcg

If the results look abnormal or unexpected you’ll have a possible explanation.

[Recon in reply to PurpleNails]

Got it, thanks. So many things to remember!

[SeasideSusie Remembering in reply to Recon]

Recon

It's actually 400mcg and 5,000mcg (micrograms) not mg (milligrams) that PurpleNails is referring to.

Most B Complex contain around 400mcg biotin and most stand alone biotin supplements or hair and nail supplements contain 5,000-10,000mcg or 5mg-10mg.

With a B Complex leaving off for 3 days should be sufficient not to make any difference, with the larger doses then 7 days is recommended.

It's not known how biotin affects the results, ie higher or lower than normal levels.

Most labs use biotin in the testing procedure and this is what causes the problem when we take a biotin supplement.

I don't think you can know for sure if your results will be unaffected.

[Recon in reply to SeasideSusie]

Thanks - I will wait and see, and hope that it doesn't do anything that will make the endo think I need a change (I'm feeling good on what I am on now and would hate if she decided I needed a reduction) I might go ahead and pay for a private test if it comes back weird. I wonder if the doc would even know about the effects of biotin, etc. on the tests - sometimes (like a lot of times) it seems they don't know much.

[SeasideSusie Remembering in reply to Recon]

I wonder if the doc would even know about the effects of biotin, etc. on the tests - sometimes (like a lot of times) it seems they don't know much.

One hopes so, it's actually on a lot of the print outs of NHS results we see here on the forum. If doctor wants to reduce dose then just say you forgot to stop biotin before the test and you understand that biotin can interfere with results and should be stopped for a few days before testing, so can you repeat the test without taking biotin.