Serum thyroglobulin level in newly detected thyrotoxicosis and its role in differential diagnosis of thyrotoxicosis

Abstract

Background: Elevated serum thyroglobulin (Tg) level is commonly observed in various forms of thyrotoxicosis; the levels vary according to different etiologies. This study aimed at identifying the value of serum Tg level in the differential diagnosis of common etiologies of thyrotoxicosis. Methods: This cross-sectional study was conducted at the endocrine outpatient department of a tertiary hospital in Bangladesh from March 2015 to May 2017. In this study, 200 subjects with newly detected untreated thyrotoxicosis were evaluated. Serum Tg was assayed by chemiluminescent immunometric assay. Results: Serum Tg level was raised in 48% of subjects. Subjects aged ≥40 years, and those having a family history of thyroid disorders had relatively higher thyroglobulin levels. The frequency of subjects with an elevated Tg was highest in subacute thyroiditis (89.5%) followed by toxic nodular goiter (77.3%) and Graves’ disease (32.9%); the difference in the frequencies was statistically significant (p<0.001). Median Tg was highest in the subjects with subacute thyroiditis (132.6 ng/ml) followed by toxic nodular goiter (99.55 ng/ml); those with Graves’ disease had the lowest Tg level (12.5 ng/ml); the differences in median Tg levels across the three groups were also statistically significant (p<0.001). Conclusions: Serum thyroglobulin level may be useful for the etiological diagnosis of thyrotoxicosis.