Excess biotin in the blood from supplements can cause some. Still, not all, lab test results are either falsely increased or falsely decreased, causing healthcare practitioners to misdiagnose and mistreat their patients.

Find out what supplements contain biotin, about standard tests affected by biotin, and how healthcare professionals can prepare you for testing if you take biotin.

Table of Contents

WHAT IS BIOTIN?


A water-soluble vitamin of the B complex, biotin (also known as vitamin B7 or vitamin H), is used as a dietary supplement and in medicine. Because biotin insufficiency is so uncommon, there is no recommended daily intake (RDI) for biotin supplementation; nonetheless, the recommended daily intake for individuals in the United States is between 30 and 100 mcg. 1 Biotin's effective half-life ranges from 8 to 18 hours. 2

Biotin, also known as B7, or water-soluble vitamin H, is a cofactor in enzymatic carboxylation reactions of fatty acid and branched-chain amino acid metabolism, gluconeogenesis, and the Krebs’ cycle. While the recommended daily intake of biotin is 30 mcg for adults, the average intake of this micronutrient in Western diets is about 35-70 mcg daily.

Approximately 15-20% of US adults take supraphysiologic doses of biotin-containing supplements for common hair and skin problems, weight loss, enhanced glucose metabolism, and boosting energy. Biotin also has pharmacologic indications for multiple sclerosis, malabsorption syndrome, dysregulation of mitochondrial energy metabolism, biotin-thiamin responsive basal ganglia disease, and genetic biotin deficiency. It is also used in alleviating muscle cramps in hemodialysis patients.

Unfortunately, when consumed in high doses, typically in over-the-counter supplements, biotin interferes with the biotin-streptavidin system used in many immunoassays. The biotin-streptavidin complex is reliable for its strong non-covalent bond. The strong affinity of biotin to streptavidin makes it resistant to organic solvents, denaturants, detergents, and proteolytic enzymes, as well as extremes of temperature and pH.

Impact of Biotin on Immunoassays
An excess biotin intake may adversely affect immunoassays in two different ways:

  • In competitive immunoassays, excessive biotin is likely to produce a falsely high result;
  • In immunometric or sandwich assays may result in false low results.

RESULTS FROM A LABORATORY USING BIOTIN


A powerful, exact, and stable connection spontaneously forms between streptavidin and biotin. This technology, which has been around for a while, enables the creation of sensitive, focused, and precise immunoassays.

The accuracy of immunoassays can be impacted by various interference and error causes.3-5

While taking biotin in large levels can interfere with immunoassays, taking biotin as an ingredient in a typical multivitamin carries no risk of this assay interference. 6


WHAT TYPICAL PATIENT POPULATIONS USE BIOTIN?


There is no RDI for biotin because it is thought to be extremely rare. Adults are advised to consume 30-100 mcg of biotin daily. 1 Three distinct demographics should be considered when thinking about using biotin as a supplement:

• Taking a daily multivitamin

• Therapeutic use of biotin at high doses

• OTC (Over-the-counter) lifestyle supplements containing high doses of biotin

Use of daily multivitamins: A common daily multivitamin contains the nutrient biotin. The usual dose is 30–40 mcg.

Treatment with high doses of biotin includes treating genetic diseases such holocarboxylase synthetase deficiency, biotin-thiamin-responsive basal ganglia illness, and biotinidase deficiency.7

Additionally, high-dose biotin is currently being tested in clinical settings as a possible treatment for multiple sclerosis patients. 9

OTC lifestyle high-dose biotin supplements: Some customers use supplements with high concentrations of biotin (5,000–10,000 mcg), which are now marketed to support healthy hair, skin, and nails.

 

INTERRUPTION BY BIOTIN IN IMMUNOASSAYS


According to all Roche immunoassay box inserts, patients taking biotin doses >5,000 mcg should wait at least 8 hours following the final biotin injection before a sample is taken to reduce the risk of interference.

 

PATIENT IDENTIFICATION FOR BIOTIN TREATMENT


Before doing any laboratory tests, it is crucial to inquire about patients' use of all supplements, including biotin, to ensure testing accuracy. 

TESTING OF PATIENTS


Prior to testing, it's crucial to ask patients the correct questions in both routine and emergency situations. You can identify potential interference from the outset and take it into account in your diagnostic evaluation and other important criteria by asking patients about their levels of biotin intake. Evaluation of the clinical picture should be done when making a diagnosis and a therapy decision.

 

WHAT ARE THE COMMON TESTS THAT MAY BE AFFECTED BY HIGHER-DOSE 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), cortfollicle-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 above examples. 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, after the patient has refrained from taking biotin, re-testing may be done later.

 

REFERENCES

1. Accessed on 5/26/2017 at http://www.mayoclinic.org/drugs-supplements/biotin-oral-route/description/drg-20062359.
2. Peyro Saint Paul et al., Expert Opinion Drug Metab-Txicol 2016, 12, 327–344.
3. Boscato et al. Clinical Chemistry 1998; 34(1): 27–33.
4. Kroll et al. Clinical Chemistry 1994; 40(11 Pt 1): 1996–2005.
5. Kricka, Clinical Chemistry 1999; 45(7):942–956.
6. Internal data; draft of text. Biotinidase Deficiency. 7. Wolf B. 2000 Mar 24 [Updated on June 9, 2016] edited by Pagon RA, Adam MP, Ardinger HH, et al. online resource GeneReviews®. University of Washington, Seattle; 1993–2017. Seattle (WA).
8. Kassem et al., AJNR 2014, 35(10):1990–1995
9. Sedel et al., Mult. Scler. Rel. Disord. 2015, 4, 159-169