- Measuring thyroxine and thyrotropin simultaneously in a dried blood sample on filter paper, to screen for neonatal hypothyroidism. Nagataki, S., Ishibashi, K., Ohsawa, R., Suwa, S., Tsukamoto, N., Takahashi, T., Obara, Y., Liao, Y.Y. Clin. Chem. (1980)