A radioimmunoassay system for human thyroglobulin.

A radioimmunoassay (RIA) system for thyroglobulin (Tgl) was developed. The crude Tgl was prepared from thyroid glands surgically removed for colloid goiter by ammonium sulphate fractionation. Two purified Tgls were obtained by gel filtration on Sephadex G-200 (Tgl-200) and by preparative polyacrylamide gel electrophoresis (Tgl-PAGE). Both Tgl-200 and Tgl-PAGE were used for immunization of the animals for radioiodination and as reference preparations. The double antibody RIA system using Tgl-200 may detect 1.5 microgram/l, the technique being suitable for Tgl quantification in human biological fluids. The results of the measurement in 54 children without apparent thyroid enlargement showed a rather wide range of variability of the Tgl values in basal conditions, for example 4.67-37.05 micrograms/l in a group of 29 boys aged 6 to 16 years and 4.06-31.90 micrograms/l in a group of 25 girls aged 5 to 16 years.