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Biotin: Interference with Laboratory Assays

Test code(s) 466, 478, 508, 512, 555, 556, 873, 11188, 15561, 16322, 17406, 19584, 30278, 34483

Question 1. What is the concern about biotin interference with clinical laboratory assays?

Biotin supplements, when taken in high doses, can cause interference with certain immunoassays.

Question 2. What is biotin?

Biotin is a water-soluble B vitamin (B7), a coenzyme involved in the synthesis of fatty acids, isoleucine, and valine, and in the conversion of carbohydrates to glucose. Biotin deficiency is rare, and there is no recommended dietary allowance (RDA) or recommended nutrient intake (RNI) established for biotin. Adequate intake levels for biotin are generally defined as follows1:

  • Infants and children:
    • Birth to 6 months: 5 micrograms (mcg)
    • 7-12 months: 6 mcg
    • 1-3 years of age: 8 mcg
    • 4 to 8 years of age: 12 mcg
    • 9 to 13 years of age: 20 mcg
    • 14 to 18 years of age: 25 mcg
  • Adolescents and adults:
    • 30 mcg

Question 3. Why do some people take biotin supplements?

Biotin is marketed as an aid to improve the appearance of hair, nails, and skin, and in some cases improve energy. It has also been promoted for use during pregnancy, for patients receiving dialysis, and for other medical scenarios including multiple sclerosis and inborn errors of metabolism.

Question 4. How long must a patient abstain from biotin supplementation before blood draw to avoid assay interference?

Some supplements have amounts many times the adequate intake, with megadoses in the 5,000 mcg to 10,000 mcg range. Biotin’s half-life is approximately 2 hours, so abstinence for 8 hours may be sufficient to minimize interference. However, it is highly recommended that patients taking massive biotin doses abstain for 72 hours before having blood specimens drawn for laboratory tests.2

Question 5. Why are the FDA and the laboratory concerned about people taking biotin supplements?

Some immunoassays incorporate biotin-streptavidin. The effect on laboratory testing is variable.

Question 6. Has the FDA provided any warning about assay interference caused by dietary biotin?

Yes. On November 28, 2017, the FDA issued a safety communication indicating that biotin in specimens from people taking biotin supplements may cause interference with some laboratory assays.3 The warning stated, “The FDA is alerting the public, health care providers, lab personnel, and lab test developers that biotin can significantly interfere with certain lab tests and cause incorrect test results, which may go undetected.”

Question 7. Which immunoassay tests in the standard Quest platforms are subject to biotin interference?

The following tests are subject to interference from high levels of biotin:

Question 8. Does the Quest Diagnostics Test Center provide a message recommending that patients wait a period of time after taking biotin before having blood specimens drawn for laboratory testing?

For the assays in which Quest Diagnostics has confirmation from the manufacturer that there is known interference, we are in the process of placing a message in our collection instruction section in the Test Center. The message is as follows:

“Dietary supplements containing biotin may interfere in assays and may skew results to be either falsely high or falsely low. For patients receiving the recommended daily doses of biotin, draw samples at least 8 hours following the last biotin supplementation. For patients on mega-doses of biotin supplements, draw samples at least 72 hours following the last biotin supplementation”.

Question 9. Are other immunoassays affected?

Currently we are not aware of biotin interference with other assays on our standard platforms.

Question 10. Are other types of assays, like LC-MS-based tests, affected?

In addition to immunoassays, Quest offers many tests, such as testosterone, using methods such as LC-MS. There is no evidence that biotin interferes with LC-MS assays.

Question 11. Is there any published literature on this topic?

Yes. In November 2017, an article on this topic was published in the Archives of Pathology and Laboratory Medicine.2


  1. https://ods.od.nih.gov/factsheets/Biotin-HealthProfessional/#h2 (accessed March 12, 2018).
  2. Holmes EW, Samarasinghe S, Emanuele MA, et al. Biotin interference in clinical immunoassays: a cause for concern. Arch Pathol Lab Med. 2017;141:1459-1460.
  3. US Food and Drug Administration. Biotin (Vitamin B7): Safety Communication - May Interfere with Lab Tests. USA FDA website. https://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm586641.htm. Accessed March 6, 2018.
This FAQ is provided for informational purposes only and is not intended as medical advice. A clinician’s test selection and interpretation, diagnosis, and patient management decisions should be based on his/her education, clinical expertise, and assessment of the patient.
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