High biotin concentration in blood can be a cause of misdiagnosis

April 2020 Clinical practice Willem van Altena

Biotin, also known as vitamin H or vitamin B8 is a water soluble vitamin that plays a part in metabolizing fatty acids, branched chain amino acids and neoglucogenesis. The recommended daily dose is 50 μg per day.

Ingesting biotin as part of a regular diet normally does not cause high biotin concentrations in blood that would transgress interference thresholds for in vitro diagnostic tests. However, using high-dosage biotin supplements, as happens with primary progressive multiple sclerosis (PPMS) patients, can possibly interfere with immunoassays. Results from research into this topic were recently published in Clinical Biochemistry magazine. (1)

Sinds 2016, 92 cases of suspected biotin interference were reported to the Food and Drug Administration (FDA) in the USA. Figures about the prevalence of high biotin levels in Belgian patients are not available. Biotin interference can occur in thyroid hormone assays. In several case studies biotin interference with thyroid hormone assays may have led to misdiagnosis as Graves’ disease. (2,3)

Clinical relevance

Biotin interference may be suspected when immuno assay results show a discrepancy with clinical information. A clincally relenvant biotin interference occurs when there is a high concentration of biotin in the blood, and the test is biotin-sensitive. The researchers come up with a workflow for lab scientists in order to evaluate atypical immuno assay results. These atypical results include: (1) serial dilution; (2) retesting after biotin clearing and/or retesting by using an alternative platform; and (3) confirmation of biotin presence by implementing depletion protocols or by measuring biotin concentrations directly.

The researchers hope to raise awareness surrounding biotin interference, and help prevent misdiagnosis. They suggest manufacturers of supplements need to be better informed, and patients, healthcare professionals and laboratory staff need more education on the subject. Clear directives for laboratory staff could be helpful in spreading awareness about prevention, detection and management of biotin interference.


  1. Clinical Biochemistry
  2. Thyroid
  3. Acta Clinica Belgica