What it measures
- Thyroglobulin
Who it’s for
- Follow-up after thyroid surgery or radioiodine treatment, as requested by your consultant
- Investigating some thyroid conditions alongside other tests
Why thyroglobulin is measured
After surgery and radioiodine treatment for differentiated thyroid cancer, there should be little or no thyroid tissue left, so thyroglobulin should be very low or undetectable. A level that rises over time can be an early sign the cancer has returned, which is why specialists track it. A private test can save a hospital trip between appointments, but your results should always be reviewed by your specialist team.
A note on antibodies
Some people make antibodies against thyroglobulin, which can make the result falsely low. Specialists usually interpret thyroglobulin together with an antibody result, so check with your team which tests they need.
How to prepare
- Drink a couple of glasses of water beforehand: it makes the sample quicker and easier to take.
- No fasting needed. Eat and drink as normal.
- Stop biotin (vitamin B7) supplements, often found in hair, skin and nail products, 48 hours before.
How it works at our Croydon clinic
Book online
Choose your test and a time that suits you. No GP referral needed.
A 15-minute visit
A trained clinician takes a small blood sample at 169 Shirley Road, Croydon. Tell us if you’re nervous.
Results in 1–3 days
A clear report showing each result against its reference range.
Next steps
Share your report with your GP, who can arrange NHS follow-up if anything needs it.
Questions
Is this a screening test for thyroid cancer?
No. Thyroglobulin isn’t used to diagnose thyroid cancer, because it’s also raised in many harmless thyroid conditions. Its main use is follow-up after treatment.
Can I share my results with my consultant?
Yes. You’ll receive a written report that you can share with your hospital team or GP.
How much is a Thyroglobulin Test in Croydon?
£85 at our clinic at 169 Shirley Road, Croydon, including taking your blood sample and your report.
How quickly will I get my results?
Usually within 1 to 3 days, in a clear report showing each result against its reference range.