Thyroglobulin (including thyroglobulin antibodies), serum
Clinical Background:
Thyroglobulin (Tg) is a glycoprotein of molecular weight 660,000. It is the principal iodoprotein of the thyroid gland and constitutes the majority of thyroid mass. The circulating levels of Tg ten...
Thyroglobulin (Tg) is a glycoprotein of molecular weight 660,000. It is the principal iodoprotein of the thyroid gland and constitutes the majority of thyroid mass. The circulating levels of Tg tend to increase in a variety of thyroid diseases including toxic and non-toxic goitre, subacute thyroiditis, Graves' disease, and carcinoma. In practice however, measurement of Tg is rarely useful in the diagnosis of disorders of thyroid function. The principal utlility of Tg measurements is in the monitoring of patients with a history of differentiated thyroid cancer who have undergone total thyroidectomy. Detectable Tg post-thyroidectomy suggests the presence of residual thyroid tissue or metastases. Serum Tg is monitored post-treatment as it is a useful marker of recurrance. Thyroglobulin autoantibodies (TgAb) are always measured alongside Tg, as TgAb can cause negative interference in immunometric Tg assays. Undetectable or low Tg concentrations should be intepreted with caution in TgAb positive samples as the measured concentration of Tg may be an under-estimate in such samples.
Test Details
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Discipline:
Biochemistry
Biochemistry
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Specimen Container Adult:
Serum
Serum
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Specimen Container Paediatric:
Serum
Serum
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Minimum Volume Adult:
2 mL blood
2 mL blood
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Minimum Volume Paediatric:
1.5 mL blood
1.5 mL blood
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Sample Stability:
2 days at 4-8°C
2 days at 4-8°C
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Transport Requirements:
Ambient
Ambient
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Interpretation:
Interpretation of Tg and TgAbs:-
Thyroglobulin <0.2 ug/L:
Post-thyroidectomy, unstimulated thyroglobulin of less than 0.2 ug/L may be considered low risk for recurrence of differentiated thyroid ...
Read MoreInterpretation of Tg and TgAbs:-
Thyroglobulin <0.2 ug/L:
Post-thyroidectomy, unstimulated thyroglobulin of less than 0.2 ug/L may be considered low risk for recurrence of differentiated thyroid cancer if there is no evidence of disease on imaging. See NICE NG230 for further details.
Thyroglobulin 0.2 to 1.0 ug/L:
Post-thyroidectomy, unstimulated thyroglobulin between 0.2 and 1.0 ug/L may be considered medium risk for recurrence of differentiated thyroid cancer. See NICE NG230 for further details.
Thyroglobulin >1.0 ug/L:
Post-thyroidectomy, unstimulated thyroglobulin greater than 1.0 ug/L may be considered higher
Thyroglobulin Antibodies <20 kU/L:
Undetectable thyroglobulin antibodies.
Thyroglobulin Antibodies 20 kU/L or greater:
Detectable thyroglobulin antibodies. Note that the presence of thyroglobulin antibodies can lead to falsely low thyroglobulin results.
Note that from 18/11/24 the assay used to measure thyroglobulin has changed from Beckman Access to Roche. The Beckman assay will be measured in parallel with the Roche assay until January 2026 to allow re-baselining of patients under long-term surveillance.
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Reference Ranges:
In treated thyroid cancer patients, a thyroglobulin value of greater than 0.1 µg/L may be indicative of recurrent/residual thyroid cancer or persistent thyroid tissue.
In treated thyroid cancer patients, a thyroglobulin value of greater than 0.1 µg/L may be indicative of recurrent/residual thyroid cancer or persistent thyroid tissue.
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Routine Contact Name:
Duty Biochemist
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Routine Telephone:
Freeman: 0191 244 8889
RVI: 0191 282 9719
Freeman: 0191 244 8889
RVI: 0191 282 9719
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Routine Email:
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Specialist Test:
Yes
Yes
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Specialist Contact Name:
Endocrine Lab
Endocrine Lab
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Specialist Telephone:
0191 282 4025
0191 282 4025