Biotin and False Results for Thyroid Labs

Biotin Vitamin B7 Article Image

Biotin and False Thyroid Test Results

Biotin (vitamin B7) is a water-soluble vitamin well known for its benefits for healthy skin, nails, hair growth, energy production, and metabolism.  It wasn’t until recently, however, when researchers reported concerns with lab test interference issues prompting the FDA to release warnings and safety alerts on its use.  The main concern relates to Biotin and false results for thyroid and other important lab tests for those who supplement.  Apparently, even a single 10-milligram (mg) dose may interfere with the accuracy of thyroid and other important test results.

Below is a Summary of the potential dangers related to high-dose supplementation

Thyroid Lab Results/Interpretation

  1. High-dose supplementation may affect the validity of thyroid labs.  People taking high doses can have thyroid labs come back normal when they’re actually low.  This is due to the way biotin interacts with the specific assays used.
  2. High-dose supplementation can cause lab results to mimic Graves’ disease that lasts several days after consumption.
  3. High-dose supplementation in infants may mimic hyperthyroidism with commercial assays.
  4. High-dose supplementation may mimic hyperthyroidism in adults.

Cardiovascular Lab Results/Interpretation

Troponins are important biochemical lab markers for heart disease measured through blood testing.  Increased levels indicate either a myocardial injury or a myocardial infarction (heart injury, or a heart attack) has occurred.  The FDA reported on a patient who had been supplementing with high levels of biotin and died following falsely low troponin lab results when a troponin test assay known to have biotin interference was used.

Sources of Vitamin B7

Biotin Graphic Food Sources of Vitamin B7Vitamin B7 is often found in multi and pre-natal vitamins.  It is also found in specialty formulas and advertised as being beneficial for healthy hair, skin, and nails.

These benefits are often motivation enough for people with thyroid disease who want to improve the health of their skin, hair, and nails since thyroid disease typically has such a negative impact on these areas.

The truth is that most people already get enough vitamin B7 from their diet.  The only groups who may be prone to deficiency are people with “biotinidase deficiency” (a rare genetic disorder), women who are pregnant and/or breastfeeding, and people with alcohol dependence.

In the United States, vitamin B7 deficiency is extremely rare.  However, a deficiency may cause:

  • Loss of body hair
  • Thinning hair
  • Brittle nails
  • Rash around the eyes, nose, mouth, and rectum
  • Skin infections
  • Pinkeye
  • Low pH (acidic) blood and urine
  • Seizures
  • Nervous system disorders
  • Infant deficiency symptoms: sluggishness, delayed development, weak muscle tone

Dangerous Lab Interference Resulting in False-Positive/Negative Results

High-dose supplementation may interfere with diagnostic testing that:

  • Are routinely used to measure thyroid hormone levels
  • Measure vitamin D (25-OH hydroxy) which may result in false normal/abnormal results
  • Use biotin-streptavidin technology

Biotin interference with lab test results may also lead to incorrect conclusions not only for troponin and thyroid labs but also for various blood testing to assess therapeutic benefit for prescription drugs, tumor markers, ferritin, vitamin B12, and folate.  Lab results for tumor markers and ferritin may come back as falsely low; whereas B12, and folate levels may be reported as falsely high.  Blood tests for immune system markers may be reported as falsely negative.

Supplementation should be discontinued at least two days (preferably seven days) prior to a blood test.  Inaccurate results are likely if testing is done less than two days after consuming the vitamin and seven days for thyroid antibody tests.

Table:  Thyroid Hormone Levels On and Off Treatment with High-Dose Biotin


Source/Image Credit: Endocrine Today, November 2016
James Robert Brennan, MD FACE; Stephanie L. Lee, MD Ph.D. ECNU

Do any of these apply to you?

Do your most recent lab results indicate:

  • Deficient ferritin despite supplementing with ferritin and/or iron, but your lab result for ferritin is low or low/normal AND you’re taking a high-dose biotin supplement (single or formula)
  • Elevated Vitamin B12 and/or folate AND you’re taking high-dose biotin supplement (single or formula)
  • Abnormal thyroid markers (FreeT3, FreeT4, TSH, Total T4, Total T3 and thyroid antibodies) that may suggest you’re leaning more toward hyperthyroidism or, autoimmune thyroid disease such as Graves’ disease, or Hashitoxicosis and your symptoms align with hypothyroidism AND you’re taking a high-dose biotin supplement (single or formula).  In this case, I highly recommend you also keep a log of the following:  basal body temperature, heart rate, blood pressure, and symptom journal to share with your prescriber.

Talk with Your Doctor

While the FDA has advised healthcare providers to ask patients about their supplements, if you are supplementing with biotin, please inform your doctor or nurse prior to any lab testing.  It may be that you’ll need to discontinue the supplement before you test for the sake of accuracy.

If any of the above apply to you discuss with your doctor the possibility of retesting after you’ve discontinued biotin supplementation for 7 days.  If it’s not possible for any reason (insurance restrictions due to the timing of previous lab test, high-deductible or co-pay, etc) you may self-order affordable lab panels for peace of mind.  Be sure to share a copy of the results with your doctor or nurse to continue the discussion and to collaborate on your next steps.

For a comprehensive thyroid panel, Thyroid Profile 9 covers everything you really need.  You may also select the following low-cost add-on labs:  Ferritin, Vitamin B12 and Folate, Vitamin D3, Tumor Markers Basic (Women)

The last thing you need with respect to thyroid and other labs (and a possible misdiagnosis due to false-positive/negative results) is interference with accuracy from a supplement.

I hope you found this article helpful.



  1. A Closer Look at the Recent FDA Safety Communication about Biotin Interference
  2. A Single 10 mg Oral Dose of Biotin Interferes with Thyroid Function Tests
  3. A Somewhat Bizarre Case of Graves Disease Due to Vitamin Treatment. Journal of the Endocrine Society
  4. Biotin:  From Nutrition to Therapeutics
  5. Biotin Treatment Mimicking Graves’ Disease
  6. Biotin (Vitamin B7): Safety Communication – May Interfere with Lab Tests
  7. False Biochemical Diagnosis of Hyperthyroidism in Streptavidin-Biotin-Based Immunoassays the problem of biotin intake and related interferences
  8. FDA Warns Biotin May Interfere with Lab Tests, Including Troponin
  9. High-dose Biotin Supplement can Interfere with Common Laboratory Tests
  10. 16 Systematic Analysis of Biotin Interference in Roche Chemistry Assays
  11. Pagana, K. D., & Pagana, T. J. (2011). Troponin. Mosby’s Diagnostic and Laboratory Test Reference (10th ed.). St. Louis, MO: Elsevier.

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