This private blood test measures serum thyroglobulin (Tg), a protein produced exclusively by thyroid follicular cells. The catalogue price is £126.25 plus a £50 phlebotomy fee, and results are usually available in 1 day.
Thyroglobulin is primarily used as a post-treatment monitoring marker after thyroidectomy or radioiodine therapy for differentiated thyroid cancer, and is typically interpreted alongside anti-thyroglobulin antibodies.
Written by Mr Stephen Lingam. Reviewed by Dr Penny Sheehan (GMC 6056535) on 18/10/2026.
No. This assay (code TGA) measures the thyroglobulin protein itself, whereas anti-thyroglobulin antibodies measure immune antibodies against thyroglobulin. Specialists often request both together.
Yes. High-dose biotin (vitamin B7) can interfere with immunoassays for thyroglobulin, so avoid biotin supplements for at least 48 hours before your blood draw.
Results are normally returned in 1 working day.
No referral is needed to book at 117a Harley Street, and you can take the formal UKAS laboratory report directly to your endocrinologist.