Britton K E, Quinn V, Ellis S M, Cayley A C, Miralles J M, Brown B L, Ekins R P
Lancet. 1975 Jul 26;2(7926):141-2. doi: 10.1016/s0140-6736(75)90053-7.
The lack of equivalence in the distrubtion of normal ranges for free thyroxine index (FT4I) and free triiodothyronine index (FT3I) in the over sixty-five age-group, as compared with the fifteen-sixty-five age-group, supports the idea that "T4 toxicosis" is a common biochemical finding in elderly women. The disparity between FT4I and FT3I ranges was also reflected in the true free T4 and free T3 levels which were measured in some cases. These results suggest that when an increased FT4I is found in an elderly woman with cardiac disease, caution should be exercised in interpreting the result as indicating that thyrotoxicosis is the cause of the cardiac disorder. Estimation of total T3, FT3I, or free T3 seems useful in confirming euthyroidism in such cases.
与15至65岁年龄组相比，65岁以上年龄组的游离甲状腺素指数（FT4I）和游离三碘甲状腺原氨酸指数（FT3I）正常范围分布缺乏等效性，这支持了“T4中毒”是老年女性常见生化表现的观点。FT4I和FT3I范围的差异也反映在某些病例中所测量的真正游离T4和游离T3水平上。这些结果表明，当在患有心脏病的老年女性中发现FT4I升高时，在将结果解释为甲状腺毒症是心脏疾病的病因时应谨慎。在此类病例中，总T3、FT3I或游离T3的测定似乎有助于确认甲状腺功能正常。
