Paper showing which thyroid hormone assays are sensitive to biotin

[diogenes]

This new paper is behind a paywall, but the abstract says all that is needed. It identifies those test manufacturers whose methods use biotin which disturbs thyroid function tests amongst others. This gives TUK posters/admin some ammunition to challenge incorrectand misleading results a) by not taking biotin, and b) by the doctor finding out what instrument was used to measure.

Thyroid Vol. 31, No. 8s

Biotin Interference in Assays for Thyroid Hormones, Thyrotropin and Thyroglobulin

Dorina Ylli, Steven J. Soldin, Brian Stolze, Bin Wei, Girum Nigussie, Hung Nguyen, Damodara Rao Mendu, Mihriye Mete, Di Wu, Cristiane J. Gomes-Lima, Joanna Klubo-Gwiezdzinska, Kenneth D. Burman, and Leonard Wartofsky

Published Online:3 Aug 2021doi.org/10.1089/thy.2020.0866

Abstract

Background: Biotin has been reported to interfere with several commonly used laboratory assays resulting in misleading values and possible erroneous diagnosis and treatment. This report describes a prospective study of possible biotin interference in thyroid-related laboratory assays, with a comparison of different commonly used assay platforms.

Materials and Methods: Thirteen adult subjects (mean age 45 ± 13 years old) were administered biotin 10 mg/day for eight days. Blood specimens were collected at three time points on day 1 and on day 8 (baseline, two, and five hours after biotin ingestion). Thyrotropin (TSH), free triiodothyronine (fT3), free thyroxine (fT4), total triiodothyronine (TT3), total thyroxine (TT4), thyroxine binding globulin (TBG), and thyroglobulin (Tg) levels were analyzed with four different platforms: Abbott Architect, Roche Cobas 6000, Siemens IMMULITE 2000, and liquid chromatography with tandem mass spectrometry (LC-MS/MS). TSH, fT3, fT4, TT3, and TT4 were measured with Abbott Architect and Roche Cobas 6000. fT3, fT4, TT3, and TT4 were also measured by LC-MS/MS. Tg was measured by Siemens IMMULITE 2000. TBG was assessed with Siemens IMMULITE 2000.

Results: Significant changes in TSH, fT4, and TT3 measurements were observed after biotin exposure when the Roche Cobas 6000 platform was used. Biotin intake resulted in a falsely lower Tg level when measurements were performed with Siemens IMMULITE 2000. At the time points examined, maximal biotin interference was observed two hours after biotin exposure both on day 1 and day 8

Conclusions: A daily dose of 10 mg was shown to interfere with specific assays for TSH, fT4, TT3, and Tg. Physicians must be aware of the potential risk of erroneous test results in subjects taking biotin supplements. Altered test results for TSH and Tg can be particularly problematic in patients requiring careful titration of levothyroxine therapy such as those with thyroid cancer.

[Hidden]

Thanks for posting this, it's interesting to see how much Biotin can impact on thyroid blood test results, it would have been interesting to see how it impacts on cortisol too although we do advise people to come off it for 6 weeks prior to testing for Cushing's or Addison's.

[helvella Administrator]

Much appreciated.

This was researched with 10 milligrams a day. Do we have any idea as to the lowest level of biotin intake which would not cause any assay interference?

I am asking because we have some members becoming (understandably) very concerned despite only taking tiny doses (150 or 300 micrograms or, as I have just seen, 100 micrograms in a B-complex product).

[diogenes Remembering in reply to helvella]

At these small levels I would say 3 days off the biotin supplement should do.

[FancyPants54 in reply to diogenes]

Hi. Having forgotten to stop my B Complex, I've screwed up my plans to retest tomorrow.

My Complex contains 300mcg of biotin. My last B Complex tablet was Friday morning. How long do you think I should wait? I'm feeling desperate for an increase in T3 but I need to get a good lab test as I've reduced by Levo. Do you think Wednesday would be OK or is it too soon and I have to wait until next week?

[diogenes Remembering in reply to FancyPants54]

It should be OK for Wednesday on this dose.

[FancyPants54 in reply to diogenes]

Thank you. I feel exhausted. The thought of another full week like this is just so depressing.

[Hidden]

Many thanks for sharing this - I’ve been taking a biotin supplement (suggested for hair loss on another forum) and it could be why my thyroid test results are not as anticipated despite meds, good diet and lifestyle (and taking into account the hurdles of NHS guidelines and the obligatory levothyroxine!)

[Tythrop]

Sorry to be thick but what is biotin? Does it have a common-or-garden name?

[SeasideSusie Remembering in reply to Tythrop]

It's one of the B vitamins - B7.

Lots of interesting information like that on Google 😉 😊

[LindaC]

Well there ya go! Thanks again, diogenes. ☘️🦋

[tattybogle]

interesting that it didn't affect fT3 only TT3.... any idea why ?

[diogenes Remembering in reply to tattybogle]

I think they omitted to mention it.

[tattybogle in reply to diogenes]

Not for the first time..

[jgelliss]

Thank you Diogenes for another Great and very Informative post. This information is very crucial. In the past I used to have labs without going off of Bioten. No Dr ever forwarns or tell us if one is on Bioten to omit it for 7days prior to doing labs .Are Dr's that ignorant uninformed. Or just don't care? At the end we are at the losing end. We do labs in good faith thinking that the results are the correct ones and not squid. How are we as thyroid patients supposed to trust our Dr's and labs?

Thank you for this Great Forum . I feel so Blessed.

[JGBH]

Many thanks Diogenes for this informative post.

[anglobike]

Thanks for this post! I will make a note of the paper and keep it on hand for my GP.