Used in biomedical research to measure free thyroxine levels in mouse serum or plasma samples. Enables assessment of thyroid function in preclinical studies, particularly in models of thyroid disorders, metabolic research, and endocrine disruption. Widely applied in pharmaceutical development and toxicology studies where rodent models are used to evaluate drug effects on the thyroid axis. Provides a reliable, high-throughput method for quantifying FT4 without interference from binding proteins.