Serum thyroglobulin in thyroid carcinoma and other thyroid disorders

Area of Science:

• Endocrinology
• Oncology
• Nuclear Medicine

Background:

• Serum thyroglobulin (hTg) is a protein produced by thyroid follicular cells.
• Accurate measurement of hTg is crucial for diagnosing and monitoring thyroid disorders.
• Interference from anti-thyroglobulin antibodies can affect assay reliability.

Purpose of the Study:

• To establish reference ranges for serum hTg in healthy individuals.
• To investigate the diagnostic utility of serum hTg in various thyroid pathologies.
• To evaluate the impact of treatment and disease progression on serum hTg levels.

Main Methods:

• Serum hTg was measured using radioimmunoassay, with exclusion of samples containing anti-thyroglobulin antibodies.
• Assay sensitivity was determined to be 1.25 ng/ml.
• hTg levels were analyzed in control subjects, pregnant women, and patients with nontoxic goiter, thyroiditis, toxic adenoma, toxic diffuse goiter, and thyroid carcinoma.

Main Results:

• Mean serum hTg in controls was 9.5 ng/ml; a slight increase was noted in pregnant women at delivery.
• Elevated hTg levels were observed in nontoxic goiter, subacute thyroiditis, toxic adenoma, and toxic diffuse goiter.
• Untreated differentiated thyroid carcinoma showed increased hTg (89.5 ng/ml), with marked elevations in cases of lymph node, bone, or lung metastases. Levels normalized post-treatment without residual disease.
• Transient hTg increases were seen after radioiodine therapy, with levels decreasing upon thyroid hormone suppression and rising after its discontinuation in metastatic cases.

Conclusions:

• Serum hTg measurement is a valuable tool for diagnosing and monitoring thyroid diseases, including differentiated thyroid carcinoma.
• hTg levels correlate with disease activity and metastatic burden in differentiated thyroid carcinoma.
• Serial hTg monitoring can aid in assessing treatment response and detecting recurrence.