Why is Biotin a recommended blood test? - Thyroid UK

Thyroid UK

141,235 members166,485 posts

Why is Biotin a recommended blood test?

kiefer profile image
6 Replies

I've noticed on many posts that Biotin, along with Vitamin D, Folate and Ferritin are recommended for testing to determine deficiencies that can cause low thyroid function.

What is the mechanism for low biotin levels affecting thyroid function? Or is it that hypothyroidism causes a biotin deficiency with the result being similar symptoms?

Just to be clear: This isn't a question about thyroid lab test results being skewed by those who take megadoses of biotin (>20mg/day).

Written by
kiefer profile image
kiefer
To view profiles and participate in discussions please or .
Read more about...
6 Replies
SlowDragon profile image
SlowDragonAdministrator

it’s not that you need biotin tested

It’s that biotin is used in many labs tests so it’s important NOT to be taking biotin before a blood test

If taking biotin and lab test uses biotin, it can cause false results

Many thyroid patients take vitamin B complex to improve low B12 and low folate

Vitamin B complex almost always contains biotin…..so it’s important to stop vitamin B complex 5-7 days before test

Biotin is also in many supplements for hair loss and brittle nails. Important to stop this at least a week before test, as likely a higher biotin dose

Lalatoot profile image
Lalatoot

Kiefer I expect what you have read is along the lines of:

"Stop biotin 3 days before testing."

What it should say is:

"Stop any supplements containing biotin 3 days before you have thyroid bloods tested."

kiefer profile image
kiefer in reply toLalatoot

What happened is that I had copied down the 4 items I had seen recommended and then a bit of sleep deprivation caused me to not refer back to the list (trusting my memory) and somehow I inserted biotin as one of the four. It's all straightened out now. Thanks.

SeasideSusie profile image
SeasideSusieRemembering

kiefer

It's B12 that is advised to test along with Vit D, Folate and Ferritin. Nowhere does anyone say to test biotin. It's advised to stop taking biotin 3-7 days before any blood test (not just thyroid) due it causing false results when biotin is used in the testing procedure (3 days for the lower dose of biotin in supplements, eg 400mcg, and 7 days for the larger amounts found in stand alone supplements and hair/nail supplements, eg 5mg or 10mg).

kiefer profile image
kiefer in reply toSeasideSusie

Yes, you're correct. my bad

Ruby1 profile image
Ruby1 in reply tokiefer

I’m glad you asked the question, as it has clarified things for me.

Not what you're looking for?

You may also like...

Biotin n blood test

Hi can I just ask n confirm I'm right in leaving off my B complex a week before thyroid blood...

Biotin n blood test

Hi Leaving off my b complex with 300ug biotin today for Thyroid blood test on Friday is that long...

A single 10mg oral dose of biotin interferes with thyroid function tests

This simple and small scale study demonstrated that even a single dose of 10 milligrams of biotin...
helvella profile image
Administrator

forgot to stop taken my biotin and levothyroxine before a blood test

Hi People, Could you tell be how the thyroid testing is affected by Biotin and levothyroxine. I...
barb62 profile image

Biotin & Blood Work

Hi. I would appreciate your thoughts regarding biotin supplementation and how much time one...
elliscp01 profile image

Moderation team

See all
Buddy195 profile image
Buddy195Administrator
PurpleNails profile image
PurpleNailsAdministrator
SlowDragon profile image
SlowDragonAdministrator

Content on HealthUnlocked does not replace the relationship between you and doctors or other healthcare professionals nor the advice you receive from them.

Never delay seeking advice or dialling emergency services because of something that you have read on HealthUnlocked.