Radioimmunoassay for Measurement of Thyroglobulin in Human Serum

A. J. Van Herle; R. P. Uller; N. L. Matthews; Josiah Brown

doi:10.1172/JCI107303

Radioimmunoassay for Measurement of Thyroglobulin in Human Serum

A. J. Van Herle, R. P. Uller, N. L. Matthews, and Josiah Brown

Published June 1, 1973 - More info

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Abstract

A specific and reproducible double antibody radioimmunoassay for the measurement of thyroglobulin (HTg) in human serum has been developed. Since antithyroglobulin autoantibodies combine with the [¹³¹I] HTg tracer, antibody-positive sera were rejected for measurement. Specificity is demonstrated in that thyroid analogous such as thyroxine (T₄), triiodothyronine (T₂) monoiodotyrosine (MIT) and diiodotyrosine (DIT) did not crossreact. Sera previously reacted with anti-HTg-Sepharose contained no immunoassayable HTg. Finally, sera obtained from patients after total thyroid ablation for thyroid carcinoma did not contain demonstrable HTg. The sensitivity of the assay is 1.6 ng/ml, and HTg was detectable in 74% of 95 normal subjects. The mean concentration was 5.1 ng/ml ±0.49 SEM (range <1.6-20.7 ng/ml). Day to day variation in HTg levels is large in some euthyroid subjects and nearly absent in others. HTg was detectable in 90% of the sera obtained in 23 pregnant women at delivery in whom a mean concentration of 10.1 ng/ml ±1.3 SEM was observed. The mean level for the corresponding newborn infants at birth was 29.3 ng/ml ±4.7 SEM a value significantly higher than the mean maternal HTg concentration (P <0.01). A group of 17 thyrotoxic individuals all had elevated HTg levels; the mean for this group was 344.8 ng/ml ±90.7 SEM. In the acute phase of subacute thyroiditis HTg was also elevated in all of 12 patients, and the mean for this group was 136.8 ng/ml ±74.6 SEM.

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