Thyroid Function Blood Test

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Thyroid Function

A thyroid function test or TFT blood test looks at the levels of thyroid stimulating hormone (TSH) and thyroxine (T4) in your blood. It can be used to detect an under-active thyroid or over-active thyroid gland.

A thyroid function test is an important component of our unwell patient screen. Do not worry about determining for yourself which if any blood test you need. This is something that your doctor will be able to determine and explain during your consultation.

All our blood tests are available same day with some of the fastest results in London. One of our doctors will take the time to explain to you what your test results mean and put in place any appropriate next steps based on those results.

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How it Works


Choose from any of our 11 London blood test clinics, open 7 days


They can advise on suitable tests and take a blood or urine sample


You will be emailed your results, analysis and recommendations


Follow up consultation only £49 for further treatment or advice

Thyroid Function and Related Tests

Please note: a GP consultation fee is payable online at the time of booking. Any tests which you require will be chargeable on top during your consultation with the doctor.

Test Cost Lab results *
DocTap Unwell Patient Screen £139 2 days


FBC with 5-part Diff


Urea and Electrolytes
Sodium, Potassium, Chloride, Bicarbonate, Urea, Creatinine, eGFR

Liver Function Tests
Bilirubin, Alk Phos, AST, ALT, Gamma GT, Total Protein, Albumin, Globulin

Glycosylated Haemoglobin


Thyroid profile
Thyroid Stimulating Hormone, Free Thyroxine (T4)

General Well Person Profile £139 1 days

Biochemistry (24 Parameters) & Haematology Profile PLUS
FT4/TSH, Ferritin
HDL Cholesterol, LDL Cholesterol and Non-HDL Cholesterol

Thyroid Profile 1 £75 1 days


Free T3 £66 1 days
Free T4 £66 1 days
T3 £66 1 days
Thyroglobulin Abs £68 2 working days
Thyroglobulin Assay £102 2 working days
Thyroid Abs (incl. Thyroglobulin + Thyroid Peroxidase Abs) £98 2 working days
Thyroid Peroxidase Antibodies/Anti TPO £68 2 working days
Thyroid Profile 2 £159 3 working days

Free T3
Free T4
Thyroglobulin Abs
Thyroid Peroxidase

Thyroid Profile 3 £114 1 days


Thyroxine (T4) £62 1 days
Thyroxine Binding Globulin £129 11 working days
TSH £66 1 days
TSH-Receptor Antibodies £162 5 working days
Well Man Profile plus HDL Cholesterol, LDL Cholesterol and Non-HDL Cholesterol £175 1 days

Biochemistry (24 Parameters) & Haematology Profile PLUS
Prostate Profile
HDL Cholesterol, LDL Cholesterol and Non-HDL Cholesterol

Well Woman Profile plus HDL Cholesterol, LDL Cholesterol and Non-HDL Cholesterol £175 1 days

Biochemistry (24 Parameters) & Haematology Profile PLUS
Vitamin D
HDL Cholesterol, LDL Cholesterol and Non-HDL Cholesterol

This is only a small sample of the many blood tests which DocTap provide. Our expert doctors can advise you during your consultation on the most appropriate tests for your condition. View all blood tests.

* Please note that the lab results are estimates and can vary. Tests taken after 1pm will be classified as the following day for timing purposes. You will receive a written analysis of your results within 1 working day of them being available from the laboratory. It is often possible for the doctor who reviews your results to be the same doctor who requested them. This is considered medical best practice but will add an additional 1 working day to the timings. If you have multiple tests then we shall wait to report on them together unless the first results highlight any reason for concern. Sometimes the preliminary results will determine that additional tests need to be carried out on your sample. If this is the case then your results will take longer. There is no additional charge for this service.

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Why Choose DocTap?

DocTap seek to provide the most convenient, fastest, effective and best value private blood testing service in London. With 8 blood test centres across London and same day appointments available 7 days a week, it has never been easier to book a tft blood test. We are proud to partner with The Doctors Laboratory (TDL) which has a worldwide reputation for excellence.

Unlike many blood test clinics, you will see a UK accredited GP who will be able to offer their expert option on what test is most appropriate for you. Your results will also be accompanied by a written analysis of what they mean and what your doctor advises you to do next. Should additional treatment be required, or if you simply wish to discuss the results in more detail, then you can book a 15 minute follow up consultation for only £25. This can either be at any DocTap clinic or over the phone. When booking your follow up consultation you can request to see you original doctor if you wish (subject to their availability).

Should you require a full consulation before deciding to have a tft blood test then there may be insufficient time to also take a blood sample in the appointment. In that case you can choose to either go to our walk in laboratory by Oxford Street (£15 phlebotomy fee applies) or to make a second appointment for the doctor to take the bloods.

TFT blood test london
Advice from expert UK doctors
8 London clinics, open 7 days
Blood tests & screens from £14
Fast results, many same day
Includes doctor's report and plan
Follow up with GP (£25, optional)
World class partner lab (TDL)
No sales incentives for doctors

What is the Thyroid Gland?

The thyroid gland is found at the front of the neck and is a small gland with a big job. The chemicals (called hormones) that it makes and releases are essential for the smooth running of the entire body. When there is a problem and too much or too little hormone is released then there can be an array of different symptoms. The thyroid gland is also connected to the pituitary gland in the brain. The pituitary can sense when too much or too little thyroid hormone is being produced and signals to the thyroid to restore the balance.

Thyroid blood tests:

  • TSH blood test - thyroid stimulating hormone is the signal from the pituitary to the thyroid gland telling it to release thyroid hormone.
  • T4 - this is the hormone released by the thyroid gland. 

What illnesses does a Thyroid Test check for?

If the level of thyroxine becomes too low, this is known as hypothyroidism. This can make you feel tired or cold, gain weight, lose hair or lead to depression. These are common symptoms that can be caused by a range of health problems, often no cause can be found, so it is important that your thyroid gland function is tested with a simple blood test to ensure that an under-active thyroid isn't missed. 

If the level of thyroxine is too high, this is known as hyperthyroidism. This can lead to weight loss, heat intolerance, palpitations and eye problems.

There are many reasons why the thyroid can become disrupted. The most common are autoimmune conditions - which is where the body wrongly attacks itself. The immune system stops recognising the thyroid as part of the body and sees it as a foreign invader.

Both under-active and overactive thyroid conditions can be treated, either with medication or sometimes with other treatments such as surgery. The blood tests are also used to monitor the response to treatment and ensure that the medication is dosed at the correct levels. 

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Our doctors are available now and can perform diagnosis and blood tests for over 1000 conditions. To see a GP regarding a TFT blood test or for any other reason book an appointment now and start feeling better right away.

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