The Hidden Impact of Biotin on Your Lab Tests: What You Need To Know

Stop biotin before getting your lab tests done to avoid confusion and costly redos!

Sarah was 23 years old when she was diagnosed with Grave’s disease. She was suffering from excessive hair loss and tried several topical creams and lotions, alongside a hair growth supplement per her dermatologist’s advice. Upon getting a second opinion, she was advised to stop the supplement and two days later got repeat thyroid testing, which turned up normal!

Imagine going to the doctor for routine tests, only to find out the results are completely off due to a vitamin supplement. This is the hidden issue with a popular supplement for hair, skin, and nails - biotin.

Understanding Biotin: More Than Just a Beauty Supplement

Biotin, also known as vitamin B7 or vitamin H, is a water-soluble B-complex vitamin that plays a crucial role in our body's metabolism. It helps convert the food we eat into energy by assisting in the breakdown of fats, carbohydrates, and proteins [1]. Biotin is naturally present in many foods, including eggs, salmon, avocados, and nuts.

While most people get enough biotin from their diet, supplements have gained popularity for their purported benefits for hair, skin, and nail health. Additionally, biotin in higher doses is used medically to treat certain conditions:

1. Biotin deficiency
2. Brittle nail syndrome
3. Neurological disorders (in experimental treatments)

The recommended daily intake for adults is 30 micrograms, but many supplements contain much higher doses, sometimes up to 10,000 micrograms or more [1].

The Rising Trend of Biotin Supplementation

In recent years, we’ve seen a significant increase in patients taking biotin supplements. The  biotin supplement market has been growing rapidly among all the majority of populations studied since the 2010s.

People are drawn to biotin's promises of stronger nails, thicker hair, and healthier skin. However, this trend has led to an unintended consequence: interference with laboratory tests.

How Biotin Affects Lab Tests

The issue with biotin and lab tests lies in the technology used for many common medical tests. Many of these tests use a system called biotin-streptavidin interaction [2]. In simple terms, these tests use biotin as a key component to measure levels of hormones, vitamins, and other substances in your blood.

When a person has high levels of biotin in their blood from supplements, it can interfere with these tests, leading to falsely high or falsely low results [3]. This interference can potentially lead to misdiagnosis or improper treatment.

Tests Affected by Biotin

The range of tests affected by biotin is surprisingly broad. Some of the most critical tests that can be impacted include:

1. Thyroid Function Tests:
   • Thyroid Stimulating Hormone (TSH)
   • Thyroxine (T4)
   • Triiodothyronine (T3)
2. Cardiac Markers:
   • Troponin (used to diagnose heart attacks)
   • B-type natriuretic peptide (BNP)
   • NT-proBNP (N-terminal pro b-type natriuretic peptide)
3. Hormones:
   • Parathyroid hormone (PTH)
   • Follicle-stimulating hormone (FSH)
   • Luteinizing hormone (LH)
   • Human chorionic gonadotropin (hCG, used to detect pregnancy)
   • Testosterone
   • Estradiol
   • Insulin
4. Infectious Disease Tests
   • Certain HIV tests
   • Hepatitis B and C tests
5. Others:
   • Vitamin D
   • Prostate-Specific Antigen (PSA, used to screen for prostate cancer)

This list is not exhaustive, and research continues to uncover more tests that can be affected by biotin[4].

Real-World Implications

The consequences of biotin interference can be serious. For example, patients like Sarah can be misdiagnosed with thyroid and other conditions due to biotin-affected test results [7]. To make things more confusing, patients often takin biotin supplements because they are experiencing excessive hair loss, which is a key feature of thyroid disease!

What’s even more confusing is that tests do not result in a direction that is necessarily predictable. While it can be tempting to guess whether your test is falsely high or low based on biotin’s affect on a particular assay, studies have shown that even the pros get it wrong.

What You Can Do

If you're taking biotin supplements or considering starting them, here are some important steps to take:

1. Inform Your Healthcare Provider: Always tell your doctor about all supplements you're taking, including biotin.
2. Read Labels Carefully: Biotin can be present in multivitamins and B-complex supplements, not just in standalone biotin products.
3. Check for Quality: Since the FDA doesn’t regulate supplements, you should look for other labeling and proof of quality. Third-party organizations will verify whether a supplement contains what is stated on the label (and doesn’t contain high levels of contaminants). USP, Labdoor, and Consumerlabs are examples of testing organizations.
4. Stick to Recommended Doses: Don’t be tempted to take more of a supplement than is recommended by your doctor or, at least, the supplement label. More is not better in this case.
5. Pause Your Supplements: If you have upcoming lab tests, ask your doctor if you should temporarily stop taking biotin. The FDA recommends stopping biotin consumption at least 72 hours before blood tests [5]. In practice, it may be fine to stop biotin supplements 24-48 hours for blood levels to be low enough not to affect tests.
6. Question Unexpected Results: If you receive test results that don't align with how you're feeling, ask your doctor if biotin could be interfering.

Other medications and supplements to be aware of before testing

Supplements that Interfere with Laboratory Tests

• Vitamin C (Ascorbic Acid)
  • Can interfere with glucose measurements, leading to falsely high or low results depending on the assay method used.
  • May affect certain fecal occult blood tests, leading to false-negative results.
• Vitamin E (Tocopherol)
  • Can affect coagulation tests, leading to falsely elevated prothrombin time (PT) and international normalized ratio (INR).
• Vitamin K
  • Can interfere with anticoagulant therapy monitoring, affecting PT and INR measurements.
• Calcium and Magnesium Supplements
  • High doses can interfere with electrolyte assays and certain hormone assays, leading to inaccurate measurements of serum calcium and magnesium levels.
  • Calcium can also make your bones appear denser than they are if you take it in the 24 hours prior to a bone density scan (such as to monitor for osteoporosis).
• Niacin (Vitamin B3)
  • Can affect liver function tests, leading to falsely elevated liver enzyme levels (e.g., ALT, AST).
• Herbal Supplements
  • Ginseng: Can interfere with coagulation tests, leading to falsely prolonged PT and INR.
  • St. John’s Wort: Can affect drug metabolism assays, leading to inaccurate drug level measurements.
• Iron Supplements
  • Can interfere with fecal occult blood tests, leading to false-positive results.
  • High doses can affect certain liver function tests, leading to elevated liver enzyme levels.
• Creatine
  • Can affect renal function tests, leading to elevated creatinine levels and potentially masking true kidney function.

Medications that Interfere with Laboratory Tests

1. Antibiotics (e.g., Rifampin)
   • Can interfere with liver function tests and certain hormone assays.
2. Diuretics
   • Can affect electrolyte assays, leading to altered levels of sodium, potassium, and other electrolytes.

Just pause your biotin 2 days prior to testing

Whether biotin is effective for hair growth or not is a topic for a different article. But regardless of whether you choose to take biotin, just remember to pause it at least 12 hours prior to testing, and preferably 24-48 (or even 72 like the FDA recommends) hours before you get your bloodwork drawn. Same for other medications and supplements, unless your doctor has given you the OK to continue them through testing.

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References:

1. Institute of Medicine (US) Standing Committee on the Scientific Evaluation of Dietary Reference Intakes and its Panel on Folate, Other B Vitamins, and Choline. Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline. Washington (DC): National Academies Press (US); 1998.
2. Colon PJ, Greene DN. Biotin Interference with Clinical Immunoassays. Journal of Applied Laboratory Medicine. 2018;2(6):941-951.
3. Li D, Ferguson A, Cervinski MA, Lynch KL, Kyle PB. AACC Guidance Document on Biotin Interference in Laboratory Tests. The Journal of Applied Laboratory Medicine. 2020;5(3):575-587.
4. Bowen R, Benavides R, Colón-Franco JM, et al. Best practices in mitigating the risk of biotin interference with laboratory testing. Clinical Biochemistry. 2019;74:1-11.
5. Center for Devices and Radiological Health. UPDATE: The FDA Warns that Biotin May Interfere with Lab Tests: FDA Safety Communication. U.S. Food And Drug Administration. Published November 5, 2019. https://public4.pagefreezer.com/content/FDA/16-06-2022T13:39/https://www.fda.gov/medical-devices/safety-communications/update-fda-warns-biotin-may-interfere-lab-tests-fda-safety-communication‌
6. Li D, Rooney MR, Burmeister LA, Basta NE, Lutsey PL. Trends in Daily Use of Biotin Supplements Among US Adults, 1999-2016. JAMA. 2020;324(6):605-607. doi:10.1001/jama.2020.8144
7. Odhaib SA, Mansour AA, Haddad NS. How Biotin Induces Misleading Results in Thyroid Bioassays: Case Series. Cureus. 2019;11(5):e4727. Published 2019 May 23. doi:10.7759/cureus.4727
8. Li D, Radulescu A, Shrestha RT, et al. Association of Biotin Ingestion With Performance of Hormone and Nonhormone Assays in Healthy Adults. JAMA. 2017;318(12):1150–1160. doi:10.1001/jama.2017.13705

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Until next time - Cheers to your health!

Hillary Lin, MD