In congenital hypothyroidism the TSH level reaches at age 5 days values about 100-times of the normal. Due to this fact, and having a good RIA-method for TSH at hand, the possibility of TSH-determination in dried whole blood on a filter-paper was examined. Control studies with normal blood-samples proved that the values of dried-blood samples had sufficient accuracy. On the 5th day of life the normal TSH-values were below 20 μU/ml while values above 100 μU/ml were suspicious for hypothyroidism. In 1200 newborns the TSH-screening was performed in combination with the routine Guthrie-test. Among them one child with a value above 100 μU/ml proved to have hypothyroidism. The results show that the determination of TSH in dried blood is possible, and that the method described is a useful tool for the early diagnosis of primary hypothyroidism.
Illig, R., & Rodriguez de Vera Roda, C. (1977). MOGLICHKEIT EINER TSH SCREENING METHODE ZUR ENTDECKUNG DER HYPOTHYREOSE BEI NEUGEBORENEN. Padiatrie Und Padologie, 12(Suppl. 5), 129–134. https://doi.org/10.1007/978-3-7091-8491-2_14