Can thyroid hormone mimics affect thyroid hormone measurement by immunoassay?

Area of Science:

• Environmental Science
• Endocrinology
• Analytical Chemistry

Background:

• Tetrabromobisphenol A (TBBPA) is an environmental pollutant and a known thyroid mimic.
• Thyroid hormone measurements are crucial for diagnosing endocrine disorders.
• Potential interference from environmental contaminants like TBBPA in diagnostic assays needs investigation.

Purpose of the Study:

• To evaluate the interference of TBBPA with thyroid hormone measurements using various immunoassays.
• To determine if TBBPA can cause false positive results in thyroid hormone testing.

Main Methods:

• Thyroid hormone-stripped human serum was spiked with TBBPA at relevant concentrations.
• The spiked serum samples were analyzed using six different commercially available thyroid hormone immunoassays.
• Assays included T4 radioimmunoassay (RIA) and other common immunoassay platforms.

Main Results:

• TBBPA did not yield positive results in most tested thyroid hormone immunoassays.
• Marginally positive results were observed only at very high TBBPA concentrations, exceeding levels typically found in exposed individuals.
• One in-house T4 radioimmunoassay (RIA) showed a weak positive at supra-physiological TBBPA levels.

Conclusions:

• Serum TBBPA, even at levels associated with occupational exposure or use as a flame retardant, is highly unlikely to cause false positive thyroid hormone results.
• Current thyroid hormone immunoassays appear robust against interference from TBBPA at realistic exposure levels.
• This finding supports the reliability of thyroid hormone testing in populations exposed to TBBPA.