Biotin Interference in Assays for Thyroid Hormones, Thyrotropin and Thyroglobulin

Area of Science:

• Clinical Chemistry
• Endocrinology
• Laboratory Medicine

Background:

• Biotin interference in laboratory assays can cause diagnostic and treatment errors.
• Thyroid function tests are crucial for diagnosing and managing thyroid disorders.

Purpose of the Study:

• To investigate biotin interference in various thyroid-related laboratory assays.
• To compare the impact of biotin on different assay platforms.

Main Methods:

• A prospective study involving 13 adult subjects taking 10 mg biotin daily for 8 days.
• Blood samples were collected at baseline and at 2 and 5 hours post-ingestion on days 1 and 8.
• Thyroid hormones (TSH, fT3, fT4, TT3, TT4), TBG, and Tg were measured using Abbott Architect, Roche Cobas 6000, Siemens IMMULITE 2000, and LC-MS/MS platforms.

Main Results:

• Significant alterations in TSH, fT4, and TT3 levels were observed with the Roche Cobas 6000 platform.
• Biotin intake led to falsely decreased thyroglobulin (Tg) measurements on the Siemens IMMULITE 2000 platform.
• Maximal interference occurred approximately two hours after biotin ingestion on both study days.

Conclusions:

• A daily 10 mg biotin dose interferes with TSH, fT4, TT3, and Tg assays.
• Physicians must be aware of potential biotin interference to avoid erroneous thyroid test results.
• Inaccurate TSH and Tg results can complicate management for patients, especially those with thyroid cancer requiring levothyroxine therapy.