A thorough understanding of thyroid physiology and its laboratory evaluation is essential for accurate diagnosis and monitoring of thyroid disorders. This session will revisit fundamental principles of thyroid function with an emphasis on clinical chemistry applications. Participants will examine the hypothalamic-pituitary-thyroid (HPT) axis and its regulatory feedback mechanisms, review the synthesis, secretion, and transport of thyroid hormones and precursors, and discuss the roles of commonly used thyroid function tests. The session will incorporate game-based learning using an audience response system.