Immunoassay of thyroxine in neonates using dried blood samples

摘要

In the immunoassay of thyroxine using dried blood samples spotted on filter paper, the assay in this invention is run at a pH of 9. 2 to 10.0, preferably at about 9.5, rather than the pH range of about 8.4 to 8.7 generally used in the art. The advantage of this higher pH range is that more accurate results are obtained with neonatal specimens. An additional advantage is that the blank or nonspecific binding is lower for many immunoassay procedures.