All Women's Blood Tests
Thyroid Function Test Clinic test
Thyroid

Thyroid Function Test

A five-marker thyroid panel — TSH, free T4, free T3 and the two thyroid antibodies — to show whether your thyroid is under- or over-active and whether an autoimmune process is behind it.

Price £75 £58.99
Covers 5 markers
Type Clinic visit · ~15 min
Book just this test
Blood sample — taken at 44 Crawford Street, Marylebone
No fasting. If you take levothyroxine, tell us — we may suggest a morning slot before your dose.
Results explained by our clinical team
About this test

Everything you need to know about Thyroid Function Test

Thyroid problems are up to ten times more common in women than in men, and they tend to surface at times of hormonal change — after a pregnancy, around the menopause, or alongside other autoimmune conditions. The symptoms — tiredness, weight change, feeling cold or hot, low mood, hair thinning, irregular periods — overlap with so much else that a blood test is the only way to know.

This panel measures Thyroid Stimulating Hormone (the pituitary’s signal to the thyroid), the active hormones free T4 and free T3, and antibodies against thyroid peroxidase (anti-TPO) and thyroglobulin (anti-TG). The antibodies matter because autoimmune thyroid disease — Hashimoto’s or Graves’ — is the most common cause, can be found years before the hormones drift, and is worth knowing about before or during pregnancy.

What's measured

What's included

5 markers in this test

Anti-TG Anti-TPO Free T3 Free T4 Thyroid Stimulating Hormone
Thyroid Stimulating HormoneThe pituitary’s instruction to the thyroid — high when the thyroid is under-active, low when it is over-active.
Free T4The main hormone the thyroid produces.
Free T3The active form your cells use.
Anti-TPOAntibodies against thyroid peroxidase — the usual sign of autoimmune thyroid disease.
Anti-TGAntibodies against thyroglobulin, often raised alongside anti-TPO.
Who it's for

Worth considering if

  • Persistent tiredness, weight change, feeling unusually cold or hot
  • Irregular or heavy periods, or difficulty conceiving
  • Planning a pregnancy, or symptoms in the year after giving birth
  • A family history of thyroid disease or another autoimmune condition
Important: A blood test is not a diagnosis on its own. Where something needs looking at, we tell you what it means and what to do next. If you are unwell now, please see your GP or call 111 rather than waiting for a test.
What to expect

Your visit

1

Book online

Add this test — and any others — to your booking, pick a time at the clinic and pay online. No fasting. If you take levothyroxine, tell us — we may suggest a morning slot before your dose.

2

Your visit

About 15 minutes at 44 Crawford Street, Marylebone. Our clinical team takes your sample (blood sample) and answers any questions.

3

Results explained

The laboratory analyses your sample and your results are released to your secure account with a written explanation from our clinical team — and a call where something needs talking through.

Frequently Asked

Thyroid Function Test — FAQs

Why test antibodies as well as hormones?
Hormone levels tell you how the thyroid is working today. Antibodies tell you whether your immune system is attacking the gland — which can happen for years before the hormones drift. Finding antibodies early means you can be monitored before symptoms build, and it matters when planning a pregnancy.
Do I need to fast?
No. Thyroid markers are not affected by food. If you take thyroid medication, tell us when you book — results are usually best interpreted from a morning sample taken before your dose.
Can thyroid problems affect fertility or pregnancy?
Yes. An under-active thyroid can disrupt ovulation and is linked to miscarriage and complications if untreated, which is why checking before and during pregnancy is sensible. Treatment is simple and effective.
Can supplements affect the result?
High-dose biotin (often in hair and nail supplements) can interfere with some thyroid assays. If you take it, stop for two days before your appointment, or let us know so the laboratory can account for it.
Where is the test done?
44 Crawford Street, London W1H 1JS — a short walk from Marylebone and Edgware Road stations. Your sample is taken at the clinic by our clinical team; you do not need to bring anything.
How long does the appointment take?
About 15 minutes. If you have booked several tests they are all done in the same visit.
Can I book several tests at once?
Yes. Use “Add to booking” on each test and then “Book” in the bar at the bottom — they go into one appointment and one payment. Home test kits are ordered separately, because they are posted to you.
How do I pay, and can I cancel?
Pay online when you book — by card or bank transfer — or at the clinic where that option is offered. You can cancel or reschedule up to 24 hours before your appointment for a full refund.
How do I get my results?
Results are released to your secure account and explained by our clinical team in a written summary, with a call where something needs talking through. Turnaround depends on the test: routine blood panels are quicker than genetic or DNA analysis, and we tell you what to expect at your appointment.
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