Used in biomedical research to measure thyroxine (T4) hormone levels in rat serum or plasma samples. Enables assessment of thyroid function in preclinical studies, particularly in endocrinology, toxicology, and drug development. Supports investigation of thyroid-related disorders, hormonal imbalances, and the impact of pharmaceuticals or environmental factors on the hypothalamic-pituitary-thyroid axis in rodent models. Provides a sensitive and specific quantitative analysis, ideal for high-throughput screening and longitudinal studies.