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Thyroid Function Blood Test

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Original price £39.00
Original price £39.00 - Original price £39.00
Original price £39.00
Current price £37.00
£37.00 - £37.00
Current price £37.00

A perfect test for symptoms such as weight gain, fatigue, or hair loss, as well as a family history of thyroid disorders.

  • Biomarkers: 3
  • Turnaround: 1-2 days

Simple and accurate blood test from a laboratory you can speak to.

Step 1. Choose sample collection option

Currently selected option: HOME KIT via Royal Mail Tracked 24

  • Available everywhere in mainland UK.
  • Includes everything you need to take a safe and suitable blood sample in about 15 minutes.
  • Post the sample back to our laboratory via Royal Mail Tracked 24.

Re-test guarantee

About the test

We provide private thyroid function blood tests taken from the comfort of your own home or in one of our clinics. Our simple test kits offer reliable, rapid results, allowing you to monitor your thyroid function and take control of your health with ease. Alternatively, pop into one of our clinics and have us take the blood sample for you.

If you experience symptoms such as weight gain, fatigue, or hair loss, or have a family history of thyroid disorders, our Thyroid Function Blood Test is perfect for you. Our CQC-regulated laboratory and advanced technology ensure the accuracy of your results, giving you peace of mind efficiently and effectively.

And with our free Health Dashboard tool online, you can track your biomarkers over time and compare your results with previous ones. This feature provides a clear understanding of how your health is progressing and helps you make better-informed decisions about your well-being.

Take the first step towards controlling your thyroid health and book a home test kit for thyroid function today.

What is a Thyroid Function Blood Test?

The thyroid gland regulates metabolism and problems with the thyroid can cause a wide variety of symptoms, some of which may be vague and easy to miss in the early stages of disease.

The Thyroid Function Test checks for three different thyroid hormones which, taken together, give an accurate picture of the health of your thyroid and may even pick up an early problem before you have any symptoms.

These hormones are the two hormones that are produced by the thyroid (T3 and T4) and the hormone that is produced in the brain that stimulates the thyroid (Thyroid Stimulating Hormone or TSH).

3 Biomarkers

  1. HORMONES

    - Unbound thyroxine (Free T4)
    - Unbound triiodothyronine (Free T3)
    - Thyroid Stimulating Hormone (TSH)

  2. UPGRADE

    Need more biomarkers? Check out the Ultimate Thyroid Function Blood Test.

  1. TURNAROUND TIME

    For most biomarkers our usual turnaround time is 24-48 hours, or less, from the time your sample is in our lab. We do not wait for all the results to complete before sending them to you, so you may start receiving results the same day for most cases, or as results become available.

    We are extremely proud of our very short turnaround times and a very efficient laboratory processes. Whilst we accommodate the shortest of time scales, with some results available within hours, for this particular test the usual turnaround time is:


    1-2 days

Doctor's notes

Hi, I am Dr. Adam Staten and here's my view on this test as a GP and Clinical Director at One Day Tests.

Usually, the thyroid gland in the neck and the pituitary gland in the brain work in harmony to effectively regulate your metabolism and keep you feeling well.

The brain produces Thyroid Stimulating Hormone (TSH) to prompt the thyroid to produce two hormones, thyroxine (T4) and triiodothyronine (T3).

As the levels of these two hormones rise, production of TSH in the brain is down regulated. As the levels of T3 and T4 fall, the brain produces more TSH to stimulate the thyroid gland to work harder.

Testing these three hormones together tells us how well your thyroid is functioning, helps to check pituitary function, and may even help us detect a problem with your thyroid before you have symptoms.

T3 and T4 exist in the blood in ‘free’ form or bound to proteins. The free forms are the active forms and these are what we measure to give an accurate impression of your thyroid function. Most tests for thyroid function just check TSH and T4, but a minority of people are unable to convert T4 to the more active T3 and so we check all 3 hormones to ensure that all elements of your thyroid function are working properly.

When the thyroid is underactive, everything essentially slows down. This results in weight gain, feeling cold all the time, dry skin and hair loss, and feeling tired and low. If the thyroid is overactive, everything speeds up. This causes weight loss, a racing pulse, tremor, feeling jittery and anxious, and the feeling of being too hot all the time.

Red flag symptoms for the Thyroid Function Blood Test

Even if your blood tests are normal, you should see a doctor if you have any of the symptoms below because they may be a sign of serious underlying illness. 

  • Unexplained weight loss.
  • Drenching sweats during the night.
  • Persistent fevers.
  • Progressively severe symptoms of any kind.

Your Results and Health Dashboard

The results of your Thyroid Function Blood Test will be emailed to you as a secured PDF file, ready for your GP and will also be uploaded to our Health Dashboard area of the website. It’s a unique and powerful tool, powered by our in-house clinical analysis research, to match your biomarkers across test panels and symptoms, as well as provide clinical commentary on all individual biomarkers you tested for.

The health dashboard will also provide "panel level" commentary - a birds eye view of the biomarkers that were tested. This feature allows you to view your test results and clinical commentary, and compare them to previous results, giving you a clear understanding of how your health is progressing.

By using the Health Dashboard, you can identify changes in your biomarkers and make necessary adjustments to your lifestyle. This added value is immense, as it empowers you to monitor your health and make informed decisions about your well-being.

It's free and is available with all of our tests.

Save on continuous monitoring with our subscription plan

The best way to look after your health is to do so regularly. This is easy to do with our continual monitoring plans which give you a discount on future blood tests. You choose the frequency and we'll do the rest.

When you purchase a subscription, we will deliver your home test kits or allow you to book appointments in line with your chosen frequency. You will be able to track your biomarkers over time in our powerful Health Dashboard, where results will be automatically updated for you. There is a minimum of 3 tests with any subscription, after which you can pause/restart/cancel at any time.

Special instructions

Hi, I am Stefania Brown, I am the Laboratory Manager at One Day Tests and here are the lab's special requests for the Thyroid Function Blood Test.

This test should be taken after any symptoms of short term illness have resolved.

If you are taking biotin supplements, stop taking them 72 hours before the test.

Venepuncture appointment - how to prepare

If you are coming into one of our clinics for the test, this is what you need to do before you arrive:

  • Drink plenty of water about an hour before the appointment.
  • Avoid coffee/tea/energy drinks. Water is good!
  • That’s it! We’ll do the rest.

Home test kit for Thyroid Function Blood Test - how it works

Our blood test kits are simple and convenient.

The most important step in doing a blood test at home is to read the instructions very carefully. The process is very simple, but there are a few pitfalls you need to be aware of - you will save yourself a lot of time if you do it right the first time around!

  • Full printed instructions will arrive with your kit - please read them carefully.
  • Drink plenty before taking the sample and warm your hands up in the sink with warm water for a few minutes. This will make your blood flow much better.
  • Fill the tubes to the top line. We don’t need much blood; filling tubes to the top line is about 15 drops of blood.
  • Post the samples on the same day you take them, before midday, Monday to Thursday. If you post it any other time it might get to us late or be stuck at a sorting office over the weekend. You will then have to do it again.
  • Package the sample in the same box the kit came in. Otherwise, Royal Mail or DPD will reject it. The sample tubes go into a pouch, then into a cardboard box, and then into a return envelope. All of this is provided in the kit: please use it.

We look forward to receiving your sample in our lab!

How the finger prick home test kit for Thyroid Function Blood Test works - from Dr. Adam Staten

Why choose us?

Hello! My name is Dr. Vinesh Mistry, I am part of the GP team here at One Day Tests and here is why you should trust us to test your blood.

We run our own regulated laboratories and our own accredited clinics. We manufacture our own approved home sample collection kits. Your results are looked after by our fantastic clinical governance team and our super-talented biomedical science team.

When you book your test with us - you book directly with the lab. This means accuracy and responsible duty of care, direct access to the provider and extremely fast turnaround times.

Finally, our customer services rock! You can ask the lab a question any time or you can speak to a real human. It's good to WhatsApp, email on hello@onedaytests.com or give us a call on 0845 527 07 67.

Frequently Asked Questions

Hi, I am Lana Nela, Lead Nurse, and here is what we are frequently asked about this test.

How do you test thyroid Function?

To test thyroid function we test for the two hormones that are produced by the thyroid (thyroxine and triiodothyronine). These are the active hormones that control your metabolism. Low levels suggest the thyroid is underactive, high levels suggest it is overactive. We also test the hormone secreted from the brain called Thyroid Stimulating Hormone (TSH). This helps us to establish whether thyroid problems are due to a problem with the thyroid or, more rarely, with the brain.

Why do you need to check for three different hormones?

Looking at the levels of T4, T3 and TSH together gives us a lot of information about the underlying cause of any thyroid disorder and helps us to establish where exactly the problem lies. Checking these three together can also help us identify early disease that may not yet be clinically apparent.

Should I test for antibodies as well?

Most thyroid problems are caused by autoimmune diseases – most commonly Grave’s disease and Hashimoto’s thyroiditis. The presence of autoantibodies helps us to establish that this is the case. Some people will have these antibodies but will not have a problem with thyroid function. These people may never develop thyroid disease, but they are at higher risk of doing so and may choose to have regular monitoring so that any problem is picked up early.

If you would like to test for antibodies then please have a look at our Ultimate Thyroid Function Blood Test.

Why take this test?

Hi, I am Dr. Marco Esposito and here is why it's important to take this test.
  • To see if any symptoms you have such as fatigue, weight change, or mood disturbance are related to a thyroid disorder.
  • If you have a family history of thyroid problems and are concerned you may have developed a thyroid disorder.
  • To monitor your thyroid function over time.

Is this test right for you?

Hi, I am Sandeep Patel, I am the Laboratory Director at One Day Tests. Here are the symptoms that you may wish to address with this test.

The hormones secreted by the thyroid gland regulate your metabolism. Because the thyroid is so important, when it goes wrong it can cause wide ranging and disabling symptoms.

The Thyroid Function Blood Test is a good option for those suffering with generalised symptoms such as malaise, fatigue, changes in weight or mood that may be due to thyroid disease.

  1. SYMPTOMS AND TAGS

    Anxiety, Chronic fatigue, Constipation, Dry skin, Fatigue, Feeling cold, Feeling hot all the time, Low mood, Muscle cramps, Palpitations, Thyroid, and Weight gain

Why blood tests are important.