Get a comprehensive thyroid hormone levels test

Thyroid hormone levels are measurements taken by blood test to see how well your thyroid gland is working, and check the amount of hormones your thyroid gland is producing. Thyroid hormones help control energy levels, metabolism, growth, and even fertility.

The hormones measured in a thyroid test are:

• thyroxine (T4) – one of 2 main hormones released by the thyroid
• triiodothyronine (T3) – the other main hormone released by the thyroid
• thyroid-stimulating hormone (TSH) – this manages the release of the 2 main hormones from the thyroid gland

By measuring these hormones together, we can understand how well the thyroid is working and whether it’s underactive (hypothyroidism) or overactive (hyperthyroidism).

If your thyroid hormone levels are out of balance, it can lead to a variety of physical symptoms, like:

• fatigue
• unexplained weight gain/loss
• increased sensitivity to cold/heat

Please note: the test kits available at ZAVA do not measure T3 (triiodothyronine)

You may need a thyroid test if you suspect you have thyroid problems, which can include an overactive or underactive thyroid. Thyroid problems can cause a range of symptoms, but a thyroid test can provide more specific information. The symptoms you may experience depend on whether your thyroid is overactive or underactive.

If you think you have an overactive thyroid

The most common cause of an overactive thyroid is Graves’ disease, which is responsible for 80% of cases. This is where the immune system produces antibodies that trigger the thyroid to produce too much thyroid hormone.

Other causes include nodules, medications, other hormone problems, thyroid inflammation, and (rarely) cancer.

An overactive thyroid can lead to physical and psychological symptoms.

Some of the psychological symptoms include:

• feeling nervous or irritable
• anxiety
• mood swings
• reduced sex drive

Physical symptoms to look out for include:

• sleep problems
• feeling tired and weak
• finding it hard to stay still
• sensitivity to heat and increased sweating
• muscle weakness
• diarrhoea
• weight loss
• feeling more thirsty than normal
• needing to pee more often
• feeling itchy
• swelling in your neck (if your thyroid gland is enlarged)
• an irregular and/or unusually fast heart rate (palpitations)
• twitching or trembling
• hair loss or thinning
• red or dry eyes
• vision problems

If you think you have an underactive thyroid

An underactive thyroid is most commonly caused by a condition called Hashimoto’s disease. This is an autoimmune condition where your immune system wrongly attacks and destroys your thyroid.

Other causes of an underactive thyroid include not getting enough iodine in your diet, medications, surgery, radiotherapy, or even treatment for an overactive thyroid.

The most common signs of an underactive thyroid are:

• feeling really tired
• struggling to concentrate or think clearly
• low mood or depression
• feeling cold more than usual or more sensitive to the cold
• gaining weight
• constipation
• dry skin or hair
• hair loss
• a croaky (hoarse) voice
• irregular or heavy periods

Although these symptoms aren’t always caused by thyroid problems, a thyroid test should be able to help you find out if this is the cause.

Thyroid tests work by checking a small blood sample, which is measured for the levels of the different thyroid hormones.

With our home test kit, you use a lancet device that contains a small needle to prick your finger, then you collect a sample of blood, which you send away for testing by post. If you visit your GP, they will take a blood sample from one of your veins (usually from your arm or hand).

Before your test, it’s important to tell the ZAVA team or your GP about any medications you’re taking or if you’re pregnant, as this can affect the results.

Most thyroid tests measure TSH and T4 levels, but not T3, as this isn’t always a reliable marker. However, in some cases, a doctor may want to measure T3 levels for extra information.

Although normal levels vary between labs, the approximate normal values are:

• 0.4-4.0 mU/L for thyroid-stimulating hormone (TSH)
• 9-24 pmol/L for thyroxine (T4)

If your TSH is high and your thyroxine is low, this means you may have an underactive thyroid. TSH is high because your body is trying to stimulate your thyroid to make more hormones.

If your TSH is low and your thyroxine is high, you may have an overactive thyroid. Your body is trying to reduce your thyroid hormone levels by producing less TSH.

It’s possible to get other test results, like normal T4 and high TSH, or for other conditions to cause changes in your thyroid hormone levels, which is why it’s important that your results are checked by a doctor.

You can measure your thyroid hormone levels at home with an at-home finger-prick blood test kit from ZAVA. The test measures your TSH and T4 levels. Your results will always be .

To request a thyroid function at-home blood test, you will need to:

1. Complete a short online health questionnaire for one of our doctors to review.
2. Once your request is approved, we’ll send you a test kit to use at home, which you can expect to receive within 1 to 2 business days of placing your order.
3. You’ll need to provide a small blood sample and use the pre-paid envelope provided in the kit to send it to our partner lab.
4. Your results will be ready 2 to 3 days after your sample reaches the lab in your patient account.

We’ll let you know by email when the results can be viewed in your account. However, we will never text or email your results to you.

You can always ask your GP for a blood test to check your thyroid hormone levels, but this will involve visiting your GP surgery in person and discussing your symptoms.

You will be given a medically reviewed report once a ZAVA doctor has reviewed the results of your test, this will have been provided to them by the lab. This will explain what the test results mean and what will happen next.

You’ll be able to ask any questions you have and get more clarification if anything in the report does not make sense.

If you require any treatment, our team will explain how you can access this through a specialist or your GP.

An underactive thyroid (or low T4 levels) is treated using a medication to replace the thyroid hormone that your body isn’t producing enough of.

This is usually a levothyroxine tablet, which you’ll take every day for the rest of your life. By taking the medication, your symptoms should improve, and you’ll be able to live normally.

You’ll need to have regular blood tests to check you’re taking the right dose of levothyroxine, as taking too much can cause symptoms similar to an overactive thyroid.

Rarely, some people who aren’t responding well to levothyroxine take the medication liothyronine that replaces the other thyroid hormone T3. This isn’t common, as there’s a lack of data from clinical trials supporting its use.

There are 3 main treatments for an overactive thyroid that is producing too much of the different thyroid hormones.

Medication

Medications known as thionamides can be used to stop your thyroid from overproducing hormones.

The most common medications are carbimazole and propylthiouracil. They usually start working after a few months and are taken for 12 to 18 months.

After this time, the dose may be reduced and even stopped if your hormone levels are under control, but some people need to keep taking the medication for several years or even for the rest of their lives.

These medications can come with side effects and aren't suitable for everyone, so they must be monitored by a doctor.

While your body gets used to the medication, your symptoms can be managed by taking beta blockers in the meantime.

Radioactive iodine

Most of the body’s iodine is stored in the thyroid and used to make hormones. Due to this, radioactive iodine can be used as a targeted treatment for an overactive thyroid.

After taking a drink or capsule that contains radioactive iodine, most of the radiation is targeted towards the thyroid, destroying some of it and stopping it from overproducing hormones.

Usually, a one-off treatment is enough to cure the condition.

After treatment, you’ll have to avoid children and pregnant women for 3 weeks, and you should not father children for 4 months or get pregnant for 6 months. The treatment is not suitable for pregnant or breastfeeding women or people with certain eye problems.

Surgery

In certain cases, surgery to remove part or all of your thyroid gland can be performed.

This is usually saved for people with a very swollen thyroid gland (known as a goitre), with severe eye problems caused by their overactive thyroid, or if other treatments haven’t worked.

If all of your thyroid is removed, your hyperthyroidism will be cured, but you will now permanently have hypothyroidism. This means you will need to take medication like levothyroxine for life, as your thyroid can no longer make any of its own hormones.