helvella - Biotin supplementation and testing

Biotin - also sometimes known as vitamin B7 or vitamin H and referenced by ATC Code A11HA05 - is one of the B vitamins.

In the past few years, it has been widely shown that biotin supplements can and do interfere with some blood tests. These are tests which are based on "streptin-avidin".

The origin of this was that some people trialled extremely high doses of biotin in the hope it would help with multiple sclerosis. These are doses such as 300 to 500 milligrams - around a thousand times more than usual supplements. Possibly more than had ever previously been taken anywhere. And some of their blood tests returned unexpected results.

Test results could be higher or lower. And differences only occurred with some analytical processes - not all.

This ended up with several papers investigating the issues. And it was shown that biotin does affect some tests.

From the beginning, no-one involved has suggested that ordinary dietary levels of biotin, the amounts we typically get from food - something like 35 to 70 micrograms a day - have any effect on tests. This would even include most foods known to have a relatively high biotin content. Aside from anything else, they would have had to develop the tests using subjects not consuming that sort of biotin levels in their diets.

Similarly, supplements of low doses were not expected to be significant. For example, up to 150 micrograms a day.

The UK Labtestonline site has this article:

Taking biotin tablets can alter some lab test results

Many people take biotin tablets because they believe they will improve their hair, skin and nails. It has been known for some years that taking large doses of biotin can effect some lab test results. The EU recommended  intake for biotin is approximately 0.05 mg (50 µg or mcg) a day, and vitamin supplements commonly contain this safe amount. However, much higher levels can be found in supplements widely promoted to benefit hair, skin and nails that contain up to 10 mg, 200 times the recommended intake, which can lead to interference in some laboratory tests.

https://labtestsonline.org.uk/news/biotin

This paper reports that the effects of up to 300 micrograms a day are unlikely to have any clinical relevance. And leaving off the supplement for two days should be sufficient on that dose.

The clinical significance of low dose biotin supplements (<300μg/day) in the treatment of patients with hypothyroidism: crucial or overestimated?

Nicholas Angelopoulos, Rodis D. Paparodis, Ioannis Androulakis, Panagiotis Anagnostis, Anastasios Boniakos, Leonidas Duntas, Spyridon N. Karras & Sarantis Livadas

Thyroid Research volume 16, Article number: 18 (2023)

Abstract

Background

In the last decade, the combination of the widespread use of streptavidin–biotin technology and biotin–containing supplements (BCS) in the daily clinical practice, have led to numerous reports of erroneous hormone immunoassay results. However, there are no studies assessing the clinical and biochemical significance of that phenomenon, when treating patients with hypothyroidism. Therefore, a prospective study was designed to investigate the potential alterations in the measurement of thyroid hormone concentrations and clinical consequences in patients with hypothyroidism using low-dose BCS containing less than 300 μg/day.

Methods

Fifty-seven patients on thyroxine supplementation, as a result of hypothyroidism and concurrent use of BCS at a dose <300μg/day for 10 to 60 days were prospectively evaluated. Namely, TSH and free T4 (FT4) concentration measurements were performed, during BC supplementation and 10 days post BCS discontinuation and compared to 31 age-matched patients with supplemented hypothyroidism and without BCS.

Results

A statistically significant increase in TSH and decline in FT4 concentrations was observed after BCS discontinuation. However, on clinical grounds, these modifications were minor and led to medication dose adjustment in only 2/57 patients (3.51%) in whom TSH was notably decreased after supplement discontinuation.

Conclusion

Our study suggests that changes in thyroid hormones profiling, due to supplements containing low dose biotin, are of minimal clinical relevance and in most cases don’t occult the need to adjust the thyroxine replacement dose in patients with hypothyroidism. Larger, well-designed trials are required to further evaluate this phenomenon.

https://thyroidresearchjournal.biomedcentral.com/articles/10.1186/s13044-023-00162-8

This paper shows that high dose, 72 milligrams a day, does have an impact. The time between last dose and test to avoid any issues is not entirely clear but seven days is almost certainly long enough.

Endocr J. 2023 Jun 17.

doi: 10.1507/endocrj.EJ23-0062. Online ahead of print.

Elevated free thyroxine and free triiodothyronine probably caused by high-dose biotin intake in a patient with Graves' disease: a case report

Kento Shimmaru 1 2 , Mitsuhiro Inami 1 , Aya Hamaoka 1 , Noriko Fujiwara 1 , Tomoaki Morioka 2 , Masanori Emoto 2 , Nozomu Kamei 1

PMID: 37331797 DOI: 10.1507/endocrj.EJ23-0062

Abstract

Biotin is a water-soluble vitamin that acts as a cofactor for carboxylase, and is often used as a component in several immunoassays. We present a case of a 46-year-old male with Graves' disease (GD) who revealed elevated free thyroxine (FT4) and free triiodothyronine (FT3) levels after high-dose biotin intake. Levels of these hormones had been within the reference range when he was on thiamazole 5 mg/day for 7 years; however, the levels increased from 1.04 to 2.20 ng/dL and from 3.05 to 9.84 pg/mL for FT4 and FT3, respectively, after he started taking biotin 72 mg/day. Despite these high levels, his symptoms and the other laboratory results, including the thyroid-stimulating hormone level, did not suggest GD relapse. His thyroid hormone data was decreased and returned within the reference range immediately after the laboratory assays for FT3 and FT4 had been coincidentally changed from those containing streptavidin-biotin complexes to biotin-free ones. Biotin interference, which is caused by high-dose biotin intake and immunoassays using some form of streptavidin-biotin complex, is sometimes clinically problematic, giving high or low results. To our knowledge, this is the first case report of a patient with GD on high-dose biotin receiving high thyroid hormone level results that were initially misunderstood as an aggravation of the disease; there are some reports of misdiagnosis of hyperthyroidism due to biotin administration. Unexpected fluctuations in thyroid function test results in patients with GD should be checked for biotin intake, immunoassays and the limiting concentration of biotin to avoid misdiagnosis of relapse.

Keywords: Biotin interference; Graves’ disease; Immunoassay; Streptavidin-biotin complex; Thyroid hormone.

https://www.jstage.jst.go.jp/article/endocrj/70/8/70_EJ23-0062/_article/-char/en

This Office of Dietary Supplements paper (from the USA) is worth reading:

Biotin
Fact Sheet for Health Professionals 

Interactions with Laboratory Tests

Very high intakes of biotin may interfere with diagnostic assays that use biotin-streptavidin technology and are commonly used to measure levels of hormones (such as thyroid hormone) and other analytes such as 25-hydroxyvitamin D, producing falsely normal or abnormal results [9,32]. As a result, a few recent case reports have described findings falsely indicating Graves’ disease and severe hyperthyroidism in patients taking 10–300 mg biotin per day, including six children receiving high doses of biotin (2–15 mg/kg body weight per day) to treat inherited metabolic diseases [33-37].

Even a single 10 mg dose of biotin has interfered with thyroid function tests administered within 24 hours of taking the supplement [38]. A small study in six healthy adults who took 10 mg/day of supplemental biotin for 1 week found interference in several biotinylated assays, including falsely decreased levels of thyroid stimulating hormone (which could lead to a misdiagnosis of thyrotoxicosis) and N-terminal pro-brain natriuretic peptide (which could result in a failure to identify congestive heart failure) [9]. According to FDA, a patient with a high intake of supplemental biotin died following a troponin test (to help diagnose a heart attack) that gave a falsely low result because the test was subject to biotin interference [32].

FDA advises health care providers to ask their patients about any supplements they may be taking that contain biotin and to consider biotin interference as a possible source of error if laboratory test results do not match the clinical presentation of the patient [32]. 

Interactions with Medications

Biotin can interact with certain medications, and some medications can have an adverse effect on biotin levels. One example is provided below. Individuals taking this and other medications on a regular basis should discuss their biotin status with their health care providers.

Anticonvulsants

In a study in 264 people with epilepsy, anticonvulsant treatment for at least 1 year was associated with significantly lower serum biotin levels than in control group patients [39]. The anticonvulsants used included carbamazepine (Tegretol, Carbatrol, Epitol, Equetro), primidone (Mysoline), phenytoin (Dilantin, Phenytek), and phenobarbital (Luminal, Solfoton) as well as combinations of these medications. A few other, smaller studies have found similar results [40,41]. The reason could be that anticonvulsant treatment increases biotin catabolism, which leads to reduced biotin status and inhibition of intestinal biotin absorption [40,42].

The above extract copied 03/01/2025. Please check for updated versions using the link below.

https://ods.od.nih.gov/factsheets/Biotin-HealthProfessional/

The UK Labtestonline says this:

Taking biotin tablets can alter some lab test results

Many people take biotin tablets because they believe they will improve their hair, skin and nails. It has been known for some years that taking large doses of biotin can effect some lab test results. The EU recommended  intake for biotin is approximately 0.05 mg (50 µg or mcg) a day, and vitamin supplements commonly contain this safe amount. However, much higher levels can be found in supplements widely promoted to benefit hair, skin and nails that contain up to 10 mg, 200 times the recommended intake, which can lead to interference in some laboratory tests.

The most striking interferences with lab test results have occurred in patients taking extremely large doses of up to 600 mg a day as part of trials for the treatment of progressive multiple sclerosis. The company sponsoring the biotin trials withdrew its application for licensing in December 2017 after the European Medicines Agency considered the available data for improvement and safety to be insufficient. The firm hopes a further large international trial will complete in 2019. Those involved are aware of biotin’s effect on lab tests.

A recent study looked at the effect of biotin and its metabolic break-down products. Dr Danni Li from the University of Minnesota and colleagues tested blood samples from six healthy adult volunteers before and after they had taken 10 mg of biotin daily for seven days. They reported the performance of 37 lab tests for 11 substances on four major diagnostic systems online in the Journal of the American Medical Association on 26 September 2017. All 37 tests used antibodies (immunoassays), 23 with a biotin-streptavidin reagent and 14 without to act as controls. None of the control results showed interference; of the 23 with biotin-streptavidin, five of the eight that used what is called a competitive immunoassay gave falsely high results while four of the 15 that used what is called a sandwich immunoassay gave falsely low results.  The authors recommend that further studies should include patients with abnormal initial test results.

On 28 November 2017 the US Food & Drug Administration (FDA) published a Safety Communication addressed to people taking or considering taking biotin supplements, doctors requesting lab tests, lab personnel and lab test developers warning about their possible effects of biotin on lab test results. It should be stressed that biotin does not affect all laboratory test results, and all manufacturers of diagnostic equipment are likely to have communicated with testing laboratories, informing them of any interferences. Individual laboratories will have then taken steps to mitigate this interference.

If you are a patient, who does take large doses of biotin, then we suggest that you discuss this with your healthcare professional, who may need to seek advice from the local laboratory.

https://labtestsonline.org.uk/news/biotin

The USA equivalent, Testing.com, says this:

What are some common tests that may be affected by biotin?

Biotin can affect a wide variety of laboratory tests. Examples include tests for:

•     Troponin—a test used to help diagnose heart attacks
•     Thyroid hormone tests, such as thyroid stimulating hormone (TSH), thyroxine (T4) and triiodothyronine (T3) tests
•     Other hormones, such as parathyroid hormone (PTH), cortisol, follicle -stimulating hormone (FSH) and luteinizing hormone (LH)
•     Vitamin D levels

Some laboratory platforms use methods that do not experience interference from biotin, even for the examples listed above. Tests that employ methods free from biotin interference can sometimes be used for re-testing samples from patients in whom biotin interference is suspected, similar to what is seen in the video, Biotin: Friend and Foe. Alternatively, re-testing may be done at a later time, after the patient has refrained from taking biotin.

https://www.testing.com/articles/biotin-affects-some-blood-test-results/

Summary

I've attempted to summarise the above into two simple statements which should ensure the worst mistakes are avoided.

If you are taking a low dose biotin supplement, anything measured in micrograms is probably low dose, leave at least two days before a blood draw. (Though their impact is likely to be small even if you do not stop taking them.)

If you are taking a higher dose biotin supplement, anything measured in milligrams is probably a high dose, leave at least seven days before a blood draw.

And if you are taking a huge dose, contact the laboratory to get up-to-date advice.

 

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[i][b]helvella - Biotin supplementation and testing[/b]

A short article about how and why biotin can affect blood tests. Includes information about how to avoid any problems and how much biotin some foods contain.

Last updated 10/02/2025[/i]

Link to blog:

https://helvella.blogspot.com/p/helvella-biotin-supplementation-and.html

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