Thyroglobulin, Serum

Test Identifier Information

Beckman Coulter Access

Post-operative monitoring in differentiated thyroid carcinoma (DTC).

See also Thyroglobulin: applications and interpretation

Specimen Collection

Take samples pre or >2 wks post any fine needle aspiration.

Patients who are undergoing biotin therapy and/or ingesting biotin supplements with levels of >100ng/mL will show a falsely low Thyroglobulin result in the Beckman Thyroglobulin assay.

Serum only

Instructions for Referral to CHLabs

CHLabs Laboratory

<0.1 - 58 µg/L in serum

Serum thyroglobulin should be undetectable (<0.1 µg/L) in a patient who has had a total thyroidectomy and has a TSH <0.1 mIU/L.

Anti-thyroglobulin antibodies (TgAb), even at low titre, may interfere with thyroglobulin measurement to cause falsely low or undetectable Tg levels.

In July 2011 the TgAb test method changed to the Roche Elecsys/Cobas method on the Roche E411 from the Beckman ACCESS method. Subsequent values will usually not be comparable to earlier values and a consequently a new TgAb baseline should be established where appropriate.

There is evidence in patients with DTC that an increase in serum TgAb on serial sampling is a risk factor for disease recurrence.

 See also Thyroglobulin: applications and interpretation

+/- 0.1 µg/L for < 0.91 µg/L,

11.0% for > 0.91 µg/L.

1. Test includes a screen for potentially interfering Tg autoantibodies (TgAb). 

In July 2011 the TgAb test method changed to the Roche Elecsys/Cobas method from the Beckman ACCESS method. Subsequent values will usually not be comparable to earlier values and a consequently a new baseline should be established where appropriate.

2. Serum is the recommended specimen, although serum or lithium heparin plasma may be used for Tg measurement, lithium heparin is not suitable for TgAb test.