Thyroid Function Test

Buy Thyroid Blood Tests Online UK

Thyroid blood tests - also known as thyroid function tests or TSH blood tests - are a quick and convenient way of checking the function of the thyroid.

The thyroid function test examines the levels of various hormones secreted from the thyroid gland and pituitary gland. The test is useful in detecting whether there is an issue with the thyroid gland and can be used in conjunction with symptoms to diagnose conditions such as hypothyroidism and hyperthyroidism.

what's the difference between the Thyroid Profile 1 and Thyroid Profile 3?

The Thyroid Profile 3 blood test detects TSH, T4 and T3 levels.

the Thyroid Profile 1 blood test only detects TSH and T4 levels. It does not detect the T3 hormone.

Where can I buy a thyroid function test kit?

You can buy thyroid test kits online, which allow you to take a blood sample from the comfort of your own home, send it off to a lab, and receive results via an email or text message within 48 hours of the lab receiving the sample.

Our thyroid blood test kits are easy to use and come with everything you need to safely acquire a sample at home and send it to our lab for testing.

What is the thyroid?

The thyroid is a small butterfly-shaped gland in the neck, just below the Adam’s apple - below the voice box (larynx) and above the collarbone (clavicle). There are two lobes connected by a section of tissue in the middle called the isthmus.

The thyroid works with the pituitary gland in the brain to release a steady flow of hormones into the bloodstream. These hormones regulate metabolism, growth, digestion, as well as the functioning of the vital organs.

The pituitary gland is located in the hypothalamus of the brain and releases thyroid stimulating hormone (TSH). This hormone acts like a thermostat for the thyroid. It detects the level of T3 in the blood and instructs the thyroid on whether it should make more or less of the hormone.

Together, the thyroid and pituitary gland make 3 hormones. The 3 hormones are commonly referred to as TSH, T4 and T3. Here's what they mean:

• TSH: Thyroid stimulating hormone is produced by the pituitary gland, located just below the brain.
• T4: The hormone known as thyroxine that contains 4 iodine atoms and is the precursor to T3.
• T3: Tri-iodothyronine is the active thyroid hormone which regulates metabolism. It has 3 iodine atoms, hence the name.

When T3 levels are low, it instructs the thyroid to produce more T4 by sending more TSH.

When the T3 levels are high, the pituitary gland instructs the thyroid not to make T4, or to make less of it.

If either the pituitary gland or thyroid gland is damaged, the levels of thyroid hormones in the blood can be affected. This can cause symptoms to develop, which may indicate an underactive or overactive thyroid.

A thyroid blood test can detect the amount of thyroid hormone in the blood, which can indicate how the thyroid is functioning.

What are the symptoms of an underactive thyroid (hypothyroidism)?

The symptoms of an underactive thyroid may include:

• brittle hair and nails
• carpal tunnel syndrome (numbness, tingling and pain in the hands and fingers)
• changes to periods (irregular or heavy periods)
• constipation
• depression
• dry and scaly skin
• low or loss of sex drive
• muscle aches, cramps, and weakness
• sensitivity to cold
• slow movements and thoughts
• tiredness
• weight gain

Underactive thyroid symptoms in women may include changes to periods, causing them to become heavy or irregular. If you notice any changes in your menstruation, speak to your doctor.

If an underactive thyroid is left untreated, it can lead to further complications, including hearing loss, anaemia or a slow heart rate.

What are the symptoms of an overactive thyroid (hyperthyroidism)?

Symptoms of an overactive thyroid can include:

• anxiety, irritability or nervousness
• mood swings
• sleep problems (insomnia)
• feeling tired or weak all the time
• sensitivity to heat
• swelling in the neck
• irregular or fast heart rate
• twitching or trembling
• weight loss

Complications can arise if an overactive thyroid is left untreated. Such complications can include eye problems, including dryness, swelling, or deteriorated vision, weight gain, depression, and complications during pregnancy.

If you are experiencing any of the symptoms listed above, it’s important to speak to your doctor first. The symptoms may be an indication of another underlying health condition, so it’s best to seek an assessment from your doctor in order to rule out other possible causes.

The symptoms alone are not enough to diagnose a thyroid problem. A thyroid blood test would be required to make a proper diagnosis.

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What Does A Thyroid Function Test Show?

Thyroid blood tests examine the amount of hormones in a given blood sample.

The thyroid profile 3 blood test looks for 3 hormones:

Generally, the normal values of these thyroid hormones are as follows:

Hormone	Range	Unit
TSH	0.4 - 4.0	mU/L (milliunits per litre)
T4	9 - 25	pmol/L (picomoles per litre)
T3	3.5 - 7.8	pmol/L (picomoles per litre)

The Thyroid Profile 1 test only tests for T4 and TSH levels.

If the level of TSH is high but the T4 levels are low, then hypothyroidism is suggested. This indicates that the thyroid is not producing enough T4 hormone, despite the increase in stimulation from TSH.

Conversely, if the TSH level is low but the T4 level is high, then hyperthyroidism is suggested. In this case, the thyroid is producing too much T4.

Depending on whether the thyroid condition is caused by the thyroid itself or the pituitary gland, it is referred to as primary or secondary respectively.

A thyroid blood test can be used in conjunction with a symptom profile to identify whether a person has a thyroid problem, such as an overactive thyroid (hyperthyroidism) or underactive thyroid (hypothyroidism).

Will I require further tests?

Depending on your symptoms and blood test results, your doctor may require further tests or may refer you to an endocrinologist - a hormone specialist.

A thyroid function test cannot detect thyroid cancer but may show results associated with cancer of the thyroid. If you feel a lump in your neck, it’s important to get it checked by your doctor.

In some cases, your doctor may suggest an ultrasound scan of your neck. This scan uses ultrasonic sound waves to create a picture of your thyroid. While they can be mildly uncomfortable, they do not hurt or take long to do. A doctor will apply a small amount of cold gel to your neck to help the scanner move more smoothly over your skin and to provide a clearer image. You may feel light pressure on your neck as the doctor moves the scanner over the skin on your neck where your thyroid gland is.

Should I Get A Thyroid Blood Test?

Before you take a thyroid function blood test, you should speak to your doctor. They will be able to inform you whether it would be worth getting tested for an underactive or overactive thyroid.

If you have been diagnosed with an underactive or overactive thyroid, your doctor may request you to take regular blood tests to monitor your condition.

Your doctor may prescribe a medicine to treat your thyroid condition. While you begin your treatment, your doctor may request regular blood tests to measure your thyroid hormone levels. This allows your doctor to monitor how you are responding to the treatment, and adjust the dosage if necessary.

What Do I Need To Know Before Taking A Thyroid Blood Test?

Some medicines can impact the results of a thyroid function test and produce inaccurate results.

It is important to speak to your doctor first before you stop taking any medicines prior to taking a blood test.

Medicines which may affect thyroid tests include:

• Amiodarone (for heart rhythm conditions)
• Anti-inflammatory drugs
• Anticonvulsants
• Contraceptive pills
• Lithium (for certain mental conditions)
• Steroids

If you are taking any of these medicines, speak to your doctor for advice before taking a thyroid function test.

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How Do I Use The Thyroid Blood Test?

Our thyroid blood test kits contain everything you need to acquire a blood sample at home and send it off to our partnered lab.

Each test kit comes with illustrated instructions to follow.

You must read these instructions before you begin.

In your thyroid test kit you will find:

• A blood collection tube
• A plaster
• A request form
• Alcoholic wipes
• An adhesive label
• Lancets

1. Start by filling out your information on the request form and the adhesive label. You should do this before you collect your sample.
2. Using the provided alcohol wipe, wipe the finger you will be drawing blood from.
3. Take one of the lancets and remove the cap from the top by twisting it.
4. Hold the lancet against your finger and press it firmly against the skin. This will release a sterile needle that will prick your finger.
5. Wipe away the first drop of blood with a tissue.
6. Hold your lanced finger over the tube so that it collects the blood. You may need to milk your finger by rubbing it from the knuckle to the nail. Do not squeeze around the site of the finger prick.
7. Once you have collected enough blood to reach the line marked on the collection tube, seal it with the lid and attach the adhesive label.
8. Place the labelled sample tube, request form, and any remaining lancets in the box.
9. Put the box inside the prepaid envelope and post it at your earliest convenience.

You must fill out the request form and put it in the box with your sample. The request form informs the laboratory what the test is for and who the test belongs to. Failing to provide this information can delay your results or void the test entirely.

Once you have collected your sample, it is important to send it off as soon as you can. Delaying posting your sample can run the risk of the sample coagulating, which renders it unusable by the lab.

We encourage you to check your local postbox to determine the best time to send the blood sample off to our lab.

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Where Can I Get A Thyroid Function Test?

You can get a thyroid function test online from Prescription Doctor.

Our test kits make it quick and simple to take a blood sample and send it to our partnered lab.

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Frequently Asked Questions

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Table of contents

Buy Thyroid Blood Tests Online UK

What Does A Thyroid Function Test Show?

How Do I Use The Thyroid Blood Test?

Where Can I Get A Thyroid Function Test?

Frequently Asked Questions

Sources

British Thyroid Foundation. British Thyroid Foundation

NHS, 2021. Underactive Thyroid (Hypothyroidism)

NHS, 2019. Overactive Thyroid (Hyperthyroidism)