[Clinical aspects of screening and diagnosis of congenital hypothyroidism in neonates in Moscow]. / Klinicheskie aspekty skrining-diagnostiki vrozhdennogo gipotireoza u novorozhdennykh Moskvy.

Screening of the newborns helped diagnose congenital hypothyrosis in infants of Moscow and define its incidence as 1 per 5000 newborns. Seventeen newborns (20%) with congenital hypothyrosis were detected among 65 ones with positive tests of more than 5 microU/ml. Clinical manifestations of this disease may be detected by specialists within the first weeks of life. Blood TTH level higher than 100 microU/ml is an evidence of congenital hypothyrosis, though one case with a lower TTH level in a newborn was detected. Levothyroxine therapy in a daily dose 50 micrograms is the optimal for the majority of such patients. For infants with transitory hypothyrosis with blood TTH levels from 40 to 80 micrograms/ml short levothyroxine therapy courses in daily doses 25-50 micrograms for 2-3 weeks may be recommended to preserve the intellectual potential of the child. All the children with blood TTH levels higher than 20 microU/ml should be regularly examined by endocrinologists and neuropathologists starting from the first days of life.

New neonatal thyrotropin enzyme immunoassay with fluorimetric detection: comparison with time-resolved fluoroimmunoassay.

This short communication compares a novel fluorimetric microplate enzyme immunoassay (FEIA) with a commercial time-resolved fluoroimmunoassay for the determination of thyrotropin in dried blood spots. The evaluation was performed using a retrospective study design with newborn blood samples from three screening centres. Non-parametric Spearman rank correlation analysis revealed highly significant positive correlation between methods: rs = 0.465, p < 0.0001 (Hannover), rs = 0.659, p < 0.0001 (Minsk), rs = 0.755, p < 0.0001 (Helsinki). Wilcoxon signed rank test performed for paired FEIA and time-resolved fluoroimmunoassay showed that the results obtained by both tests represented the same distribution (p < 0.0001). The new method, using fluorimetric detection, can be performed with the instrumentation commonly used for the screening of congenital hypothyroidism and phenylketonuria. Results are obtained within three to four hours after arrival of the sample in the laboratory. Preliminary evaluation indicates the method to be a suitable alternative to time-resolved fluoroimmunoassay for neonatal thyroid function screening.