非甲狀腺疾病症候群 (non-thyroidal illness syndrome，NTIS) 患者之內分泌檢驗數據，依病情嚴重程度而有多樣的變化。初期表現爲血中三碘甲狀腺素濃度偏低，逆三碘甲狀腺素濃度偏高，疾病的持續進一步使血中甲狀腺素濃度下降，疾病嚴重時游離四碘甲狀腺素與甲狀腺促素濃度亦會降低。作用機轉包括周邊相關激素的代謝異常、血液中結合蛋白質濃度的改變、球蛋白與激素結合力下降、下視丘與腦垂體功能失調，以及藥物對腦垂體分泌甲狀腺促素的干擾。病患的甲狀腺功能是否正常，以及是否需要補充激素仍有許多爭議。本文綜述正反雙方不同之意見，並突顯此醫療困境。

Many non-thyroidal disorders accompanied by abnormality of thyroid function tests defined as non-thyroidal illness syndrome (NTIS) are characterized by decreasing for serum triiodothyronine (T3), increasing for serum reverse T3, and, in the most severe pattern, dropping for serum thyroxine. Though thyrotropin usually remains normal, hormone changes in NTIS representing