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