Biotin: Interference with Laboratory Assays

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

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 (µg)
  • 7 to 12 months: 6 µg
  • 1-3 years of age: 8 µg
  • 4 to 8 years of age: 12 µg
  • 9 to 13 years of age: 20 µg
  • 14 to 18 years of age: 25 µg
  • 19+ years of age: 30 µg

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.

Some supplements have amounts many times the adequate intake, with megadoses in the 5,000 µg to 10,000 µg 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

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

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.”

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

For the assays in which Quest Diagnostics has confirmation from the manufacturer that there is known interference, we placed a message in our collection instruction section in the Quest Diagnostics Test Directory. 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”.

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

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

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