Lemonnier F, Masson J, Laroche D, Travert J, Travert G
Service de Biophysique et Médecine Nucléaire, C.H.R.U. de Caen, France.
Clin Chem. 1991 Dec;37(12):2114-7.
We have adapted a new radioimmunoassay for free thyroxin (FT4) measurement in dried blood spots for use in neonatal screening for hypothyroidism. The method is easy, fast, and cheap. Within-assay and between-assay CVs are respectively 9.6% and 13.2%. In 997 neonates three days postpartum with normal thyrotropin concentrations, the mean FT4 concentration was 27.2 pmol/L (SD 7.3 pmol/L). There was no significant difference in mean FT4 concentration between boys and girls. FT4 concentrations increased linearly with birth weight or with gestational age, as expressed by multiple linear regression: FT4 (pmol/L) = 0.0016 birth weight (g) + 0.6931 gestational age (weeks) - 4.8772. Only gestational age significantly affected the FT4 value. For five hypothyroid infants tested on day three postpartum, FT4 values were all below the 1st percentile of values from healthy neonates. Thus, when the neonatal concentration of thyrotropin is above normal, FT4 measured in the same sample can provide a reliable earlier diagnosis of hypothyroidism.
我们采用了一种新的放射免疫分析法来测定干血斑中的游离甲状腺素（FT4），用于新生儿甲状腺功能减退症的筛查。该方法简便、快速且成本低廉。批内变异系数和批间变异系数分别为9.6%和13.2%。在997名产后三天促甲状腺素浓度正常的新生儿中，平均FT4浓度为27.2 pmol/L（标准差7.3 pmol/L）。男孩和女孩的平均FT4浓度无显著差异。FT4浓度与出生体重或胎龄呈线性增加，多元线性回归表示为：FT4（pmol/L）=0.0016×出生体重（g）+0.6931×胎龄（周）-4.8772。只有胎龄显著影响FT4值。对于产后第三天检测的五名甲状腺功能减退婴儿，FT4值均低于健康新生儿值的第1百分位数。因此，当新生儿促甲状腺素浓度高于正常时，在同一样本中测量的FT4可为甲状腺功能减退症提供可靠的早期诊断。
