Thyroid Function Blood Test
A private thyroid function blood test measuring TSH, free T4 and free T3, the three hormones used to diagnose an underactive or overactive thyroid, for tiredness, weight change, feeling cold or hot, anxiety, low mood or hair loss. From £49 with a finger-prick kit at home, £79 at one of 250+ Goodbody clinics or £109 with a nurse home visit, no fasting needed. Results in 3 to 5 working days.... Read more
A private thyroid function blood test measuring TSH, free T4 and free T3, the three hormones used to diagnose an underactive or overactive thyroid, for tiredness, weight change, feeling cold or hot, anxiety, low mood or hair loss. From £49 with a finger-prick kit at home, £79 at one of 250+ Goodbody clinics or £109 with a nurse home visit, no fasting needed. Results in 3 to 5 working days.
Key facts
- Price: from £49 with a finger-prick kit at home; £79 at a Goodbody clinic; £109 with a nurse home visit
- Measures: thyroid stimulating hormone (TSH), free thyroxine (free T4) and free triiodothyronine (free T3); all three are reported from the finger-prick sample
- Fasting: not needed; take the sample in the morning if you can, and stop biotin supplements for two days beforehand
- Results: emailed within 3 to 5 working days with a GP report
- Step up: our Thyroid Function with Antibodies test (£109) adds the two thyroid antibodies that show autoimmune thyroid disease
- Standard: an NHS Guided Test: the same thyroid function tests your GP would order
Your questions answered
What is a TSH blood test, and what does it show?
TSH is thyroid stimulating hormone, made by the pituitary gland to tell the thyroid how much hormone to produce. It is the most sensitive single measure of thyroid function, because it moves before the thyroid hormones themselves do: a high TSH means the pituitary is pushing a thyroid that is underperforming (hypothyroidism), and a low TSH means the thyroid is overproducing and the pituitary has backed off (hyperthyroidism). Free T4 is the main hormone the thyroid makes, and free T3 is the active form it is converted into; both are measured alongside TSH to confirm the picture and show how severe it is.
How do you test for an underactive thyroid?
With this blood test. An underactive thyroid shows as a raised TSH with a low or low-normal free T4. A TSH that is raised but with a normal free T4 is called subclinical hypothyroidism and is usually rechecked in three months before any treatment is considered. Symptoms alone cannot diagnose it, because tiredness, weight gain, feeling cold, constipation, dry skin, low mood and heavy periods all have other causes; the blood test is what separates them, and it is exactly what a GP would order.
How much is a private thyroid test?
From £49 at Goodbody Clinic with a finger-prick kit posted to your home, £79 with the sample taken at one of 250+ clinics, or £109 with a nurse visiting your home, including laboratory analysis and a GP report that interprets your levels. Private thyroid function tests in the UK typically cost £40 to £90; the report is included at every price here. If you also want thyroid antibodies, our Thyroid Function with Antibodies test is £109.
Can you get a thyroid test at the chemist, or at home?
Some pharmacies sell finger-prick thyroid kits, which are the same idea as ours: a few drops of blood posted to a laboratory. There is no instant in-store thyroid test, because thyroid hormones need laboratory analysis. Our kit is £49 with a GP report included, or you can have the sample taken for you at a clinic or by a nurse at home. Every marker is reported from the finger-prick sample.
Do I need to fast for a thyroid blood test, and what can affect the result?
No fasting is needed; eating does not meaningfully change thyroid hormone levels. Three things do. Biotin supplements, common in hair and nail products, interfere with the laboratory method and can produce falsely abnormal results, so stop them for at least two days before. Time of day: TSH is highest in the early morning and lowest in the afternoon, so a morning sample is preferable and consistent timing matters if you are retesting. And if you take levothyroxine, take the sample before your dose that day, as taking it first can push free T4 up. Recent illness, pregnancy and some medications such as steroids and amiodarone can also affect results.
Does a regular blood test show thyroid problems?
Only if thyroid function is specifically requested. A routine full blood count, liver or kidney panel does not include TSH, so a thyroid problem can be missed for years while other tests come back normal. Our Essential, Advanced and Signature Well Man and Well Woman panels include TSH and free T4, and the Signature panels free T3 as well; this test is the focused option when thyroid is the specific question.
What blood tests show thyroid problems?
TSH and free T4 identify almost all thyroid disorders and are the tests the NHS uses; free T3 distinguishes types of overactivity and shows how much active hormone is available. Thyroid peroxidase and thyroglobulin antibodies show whether an autoimmune process, Hashimoto's or Graves' disease, is the cause, which matters for prognosis and for people planning pregnancy. This test covers the three hormones; our Thyroid Function with Antibodies test adds the two antibodies.
What happens if my thyroid test is abnormal?
Your GP report explains what the pattern shows. A clearly raised TSH with a low free T4 usually means treatment with levothyroxine is needed, which your GP can prescribe; a mildly raised TSH is usually repeated in three months; a low TSH with a raised free T4 needs GP referral to investigate an overactive thyroid. Take the report to your GP, who can prescribe and monitor; thyroid treatment is straightforward and lifelong, and most people feel dramatically better once levels are corrected.
How do I read my thyroid results?
Three numbers. TSH, typically with a reference range of about 0.3 to 4.5 mIU/L: above it suggests underactive, below it overactive. Free T4, typically about 10 to 22 pmol/L: low with a high TSH confirms hypothyroidism, high with a low TSH confirms hyperthyroidism. Free T3, the active hormone, moves the same way and is most useful when TSH is low. The exact ranges are printed on your report, and the GP report interprets the three together against them.
Can a thyroid blood test show cancer?
No. TSH and free T4 measure how much hormone the thyroid is making, and most thyroid cancers do not change hormone levels at all. Thyroid cancer is investigated when a lump or nodule is found, with an ultrasound scan and a needle biopsy, not with a blood test. If you have noticed a lump in your neck, difficulty swallowing or a hoarse voice, see your GP for an examination regardless of any blood result.
What are the signs of a thyroid problem?
Underactive: tiredness, weight gain, feeling cold, constipation, dry skin, thinning hair, low mood, poor concentration, heavy or irregular periods and a slow pulse. Overactive: weight loss despite a normal appetite, feeling hot and sweaty, a fast or irregular heartbeat, anxiety, tremor, trouble sleeping, frequent bowel movements and bulging or gritty eyes. Both are far more common in women, run in families, and often develop slowly enough that the symptoms are put down to age or stress. A blood test settles the question in days.
How long do thyroid blood test results take?
Results are emailed within 3 to 5 working days of your sample reaching the laboratory, with a GP report that explains your TSH, free T4 and free T3 together and what to do next, including whether a repeat, antibodies, or a GP appointment is the right step.
What happens next
Your results and GP report are emailed to you within 3 to 5 working days of your sample reaching the laboratory. The report explains each marker in plain language, flags anything outside the reference range and says what to do next, including when to take the result to your own GP. All samples are analysed by a UKAS-accredited laboratory.
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Available testing locations for Thyroid Function Blood Test
Aberdeen Clinic GCI Advanced Aesthetics
Abergavenny Clinic Amatsu Centre
Airdrie Clinic Amiry & Gilbride Pharmacy
Aldershot Clinic Wellington Pharmacy
Alton Clinic Four Marks Pharmacy
Andover Clinic Dr Malaika Clinics
Anniesland Clinic Amiry & Gilbride Pharmacy
Arlesey Clinic Waterloo Farm Wellness
Armadale Clinic Dears Pharmacy
Ascot Clinic Ascot Pharmacy
AshbyDeLaZouch Clinic Aeternum Aesthetics
Ashford Clinic Breakspear Pharmacy
Aveley Clinic Doctor B Aesthetics
Aylesbury Clinic Aura Body Clinic
Aylesbury Clinic Pearlfect Care Pharmacy
Aylsham Clinic North Norfolk Ear & Skin Care
Ballingry Clinic
Barnet Clinic Co Wellbeing
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How our blood tests work
Have your blood taken in-clinic by one of our skilled phlebotomists and check multiple biomarkers in one go. Many of our tests can also be done in the comfort of your own home with one of our easy-to-use test kits.
Testing
Take a test, either in the comfort of your own home, with a nurse visit, or at one of our clinics nationwide.
Analysis
Your sample is analysed in the clinic, laboratory or using your home test equipment.
Results
Get your comprehensive detailed results report from the laboratory.
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Meet our Goodbody Experts
Our team of professionals has decades of experience so you can be sure you’re getting the best tests and support to understand and improve your health.
Get in touch with Our Team
Dr Lebeth Jacob
BSc (Hons) MBChB
Registered GP & Lead Medical Advisor
Dr Alexandre Akoulitchev
MA, PhD, FRSM
Clinical Support Advisor
Dr Cheng Boon
MBCHB, MRCP, FRCR
Consultant Oncologist
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