建立地区、孕龄和方法特异性甲状腺激素参考值范围在妊娠期甲状腺功能评价中的作用

The establishment of regional,gestational age,method-specific thyroid function reference ranges in the evaluation of thyroid function during pregnancy

目的 建立本地区和所用仪器方法正常孕妇孕早期、中期、晚期促甲状腺激素(TSH)、游离甲状腺激素(FT4)、游离三碘甲状腺原氨酸(FT3)参考值范围,探讨使用孕前参考值范围对妊娠妇女甲状腺功能误诊率.方法 按照美国国家临床生化研究院(NACB)的标准,分别选择孕前和妊娠期妇女279和2946例,检测比较FT3、FT4、促甲状腺激素(TSH)在妊娠各期的变化规律.结果 无论用平均值还是中位数,TSH在孕8～11周时降到最低,出现谷底,随后慢慢升高至(临)产前达到孕前水平；FT3和FT4随孕周增加而降低.如果采用孕前妇女参考值范围判定妊娠各期甲状腺功能将会造成4.8％孕妇被误判TSH异常,15.1％误判为FT3异常和50％误判FT4异常.结论 每个实验室应该根据自己所用实验仪器和方法,以及服务的对象建立本地区不同孕期的参考值范围.孕期FT4下降的速度是否作为选择免疫分析方法和试剂的标准值得探讨.

Objectives To establish trimester-as well as before 9 weeks of pregnancy-and methodspecific serum reference interval for thyroid stimulating hormone(TSH),free thyroid hormones FT_4),free three triiodothyronine(FT_3) in local area.Methods According to the standards of National Academy of Clinical Biochemistry(NACB),279 women in pre-pregnancy and 2946 in pregnancy period were screened to test serum FT_3,FT_4 and TSH level variation rate in each trimester above.Results Both mean or median value of TSH were decreased to a minimum at 8-11 weeks of gestation,established of the bottom,and then increased slowly,returning the pre-pregnancy level when perinatal period nearby;FT_3 and FT_4 also showed a reduction with the gestational age growth.Diagnosis with the reference interval of pre-pregnancy women would lead misjudge in about 4.8%TSH,15.1%FT_3 and 50%aFT_4 abnormalities in each pregnancy trimester.Conclusion Laboratory specific reference interval should he based on different experimental apparatus,methods,and service objects at different gestation stages.Further study should focus on the possiblity of FT_4 decline rates as a standard for Immunoassay method and reagent selection during pregnancy.