Role of Tc-99m pertechnetate for remnant scintigraphy, post-thyroidectomy, and serum thyroglobulin and antithyroglobulin antibody levels in the patients with differentiated thyroid cancer

The use of recombinant human thyrotropin (rhTSH) testing in the diagnosis and therapy of differentiated thyroid cancer (DTC) has been adopted over the last two decades as an alternative to the classical thyroid hormone withdrawal avoiding the threat of hypothyroidism. Serum thyroglobulin (Tg) measurement is crucial for monitoring DTC patients over time. Until about a decade ago, optimal sensitivity of Tg assays for the detection of smaller disease foci required Tg measurement after thyrotropin (TSH) stimulation, carried out following thyroid hormone withdrawal or rhTSH administration. In very recent years, significant improvements in assay technology have resulted in highly sensitive Tg (hsTg) assays, sufficiently sensitive to obviate the need for rhTSH stimulation in most DTC patients. The aim of this paper is to review and discuss, via a ‘pros and cons’ approach, the current clinical role of rhTSH to stimulate radioiodine (RAI) uptake for treatment and/or imaging purposes and to increase the clinical sensitivity of Tg measurement for monitoring DTC patients when high-sensitive Tg assays are available.

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Estimation of True Serum Thyroglobulin Concentration Using Simultaneous Measurement of Serum Antithyroglobulin Antibody

International Journal of Endocrinology ◽

10.1155/2013/210639 ◽

2013 ◽

Vol 2013 ◽

pp. 1-7 ◽

Cited By ~ 6

Author(s):

Byeong-Cheol Ahn ◽

Won Kee Lee ◽

Shin Young Jeong ◽

Sang-Woo Lee ◽

Jaetae Lee

Keyword(s):

Thyroid Cancer ◽

Differentiated Thyroid Cancer ◽

Immunoradiometric Assay ◽

Mathematical Equation ◽

Excellent Correlation ◽

Serum Thyroglobulin ◽

Antithyroglobulin Antibody ◽

Analytical Interference ◽

Mathematical Equations ◽

Thyroglobulin Concentration

We investigated the analytical interference of antithyroglobulin antibody (TgAb) to thyroglobulin (Tg) measurement and tried to convert measured Tg concentration to true Tg concentration using a mathematical equation which includes a concentration of TgAb.Methods.Tg was measured by immunoradiometric assay and TgAb by radioimmunoassy. Experimental samples were produced by mixing Tg and TgAb standard solutions or mixing patients’ serum with high Tg or high TgAb. Mathematical equations for prediction of expected Tg concentration with measured Tg and TgAb concentrations were deduced. The Tg concentration calculated using the equations was compared with the expected Tg concentration.Results.Measured Tg concentrations of samples having high TgAb were significantly lower than their expected Tg concentration. Magnitude of TgAb interference with the Tg assay showed a positive correlation with concentration of TgAb. Mathematical equations for estimation of expected Tg concentration using measured Tg and TgAb concentrations were successfully deduced and the calculated Tg concentration showed excellent correlation with expected Tg concentration.Conclusions.A mathematic equation for estimation of true Tg concentration using measured Tg and TgAb concentration was deduced. Tg concentration calculated by use of the equation might be more valuable than measured Tg concentration in patients with differentiated thyroid cancer.

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