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[SILEX™ - Self Test] Under-Active Thyroid Test

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Under-Active Thyroid Test to measure the TSH level in your blood to identify an underactive thyroid.

This simple and easy to use self test can give you your results in under ten minutes from the comfort of your home, with one painless finger prick blood sample.

*This test kit is not able to identify an overactive thyroid.*


Why you need it:

  • The Under-Active Thyroid Test is crucial for the early detection of an underactive thyroid by measuring the TSH level in your blood. Early identification allows for timely intervention and management, preventing potential complications associated with hypothyroidism.
  • This self-test provides the convenience of obtaining results in under ten minutes from the comfort of your home, making it accessible for individuals who prefer a private and convenient testing option.
  • This test kit is specifically designed to identify an underactive thyroid, offering targeted insights into thyroid function. It provides clarity on whether the thyroid gland is producing an adequate amount of thyroid hormone, addressing a specific health concern.

Why we love it:

  • The test kit boasts clinically tested accuracy of over 98%, ensuring reliable results. We appreciate the high level of accuracy, providing users with trustworthy information for informed decision-making about their thyroid health.
  • The rapid result turnaround of 10 minutes contributes to the user-friendly design of the test. Additionally, the one painless finger prick blood sample minimises discomfort, enhancing the overall testing experience for users.
  • The clear communication that the test kit is not able to identify an overactive thyroid helps manage expectations. This specificity ensures that individuals seeking to detect underactive thyroid receive accurate information without confusion.

What is it (and why):

  • The primary component of the package is the Under-Active Thyroid Test, designed for measuring the TSH level in blood. This kit includes all the necessary materials for users to perform the test at home, emphasising simplicity and convenience.
  • The package contains valuable information about underactive thyroid, including symptoms and the importance of early detection. This educational content enhances users' understanding of the condition, encouraging proactive health monitoring.
  • Clear and comprehensive instructions for use are included to guide individuals through the testing process. This instructional component is crucial for ensuring accurate test performance.
how to use


Always follow the instructions provided in the package with the test.

1. Wash your hands with soap and rinse with clear warm water.

2. Bring the pouch to room temperature before opening it. Open the foil pouch and get out the cassette.

3. Carefully pull off and dispose of the released cap of the lancet.

4. Use the provided alcohol pad to clean the fingertip of the middle or ring finger as the puncture site.

5. Press the lancet, on the side from where the cap was extracted; against the fingertip (Side of ring finger is advised).

The tip retracts automatically and safely after use.

6. Keeping the hand down massage the end that was pricked to obtain a blood drop.

7. Without squeezing the capillary dropper bulb, put it in contact with the blood. The blood migrates into the capillary dropper to the line indicated on the capillary dropper.

You may massage again your finger to obtain more blood if the line is not reached.

Avoid air bubbles.

8. Put the blood collected into the sample well of the cassette, by squeezing on the dropper bulb.

9. Wait for the blood to be totally dispensed in the well. Unscrew the cap of the buffer bottle and add 2 drops of buffer into the sample well of the cassette.

10. Wait for the coloured line(s) to appear.

Read results at 10 minutes. Do not interpret the result after 20 minutes.



  • Pouch
  • Buffer
  • Lancet
  • Alcohol pad
  • Capillary dropper
  • Test cassette
[SILEX™ - Self Test] Under-Active Thyroid Test
[SILEX™ - Self Test] Under-Active Thyroid Test
[SILEX™ - Self Test] Under-Active Thyroid Test
[SILEX™ - Self Test] Under-Active Thyroid Test
[SILEX™ - Self Test] Under-Active Thyroid Test
  • Results in 10 minutes

  • Reliable detection of an under-active thyroid

  • Test at home today for your peace of mind


Frequently asked

What is an underactive thyroid?

An underactive thyroid is when your thyroid gland doesn’t produce enough thyroid hormone (thyroxine). This condition is also known as underactive thyroid or hypothyroidism.

Where is thyroxine produced?

Thyroxine is produced in the thyroid gland. The thyroid gland sits at the front of your neck.

Who is affected by an underactive thyroid?

In the UK, the prevalence of spontaneous underactive is 2%, and it is ten times more common in women than in men (1-2). The most common age group affected is 40-50 years (1-2).

What are the symptoms?

The symptoms of an underactive thyroid are often vague and usually develop quite slowly such that you may not notice them. When the body doesn’t have enough thyroid hormone many of the body’s functions slow down.

You should think about underactive thyroid with the following symptoms (most common in bold):

  • Tiredness
  • Weight gain
  • Low mood
  • Being sensitive to the cold
  • Dry skin and dry hair
  • Muscle aches, weakness and cramps
  • Constipation
  • Loss of libido (low sex drive)
  • Irregular period or heavy periods
  • Carpal tunnel syndrome
What are the complications of not treating an underactive thyroid?

If an underactive thyroid isn’t treated it can lead to complications including:

  • Heart disease: this is because low levels of thyroxine can lead to increased levels of cholesterol in your blood which can deposit in your arteries restricting the blood flow to the heart.
  • Goitre: this is an abnormal swelling of the thyroid gland that causes a lump to form at the front of your neck. This is the thyroid gland enlarging to produce more of the missing hormone.
  • Pregnancy issues: if you don’t have enough thyroxine during pregnancy there may be pregnancy related complications, including pre-eclampsia, anaemia (low red blood cells), underactive thyroid in the newborn, birth defects, problems with the baby’s development and stillbirth/miscarriage
  • Myxoedema coma: this is a rare life-threatening condition that occurs when there are severely low levels of thyroxine. Symptoms of this condition include confusion, hypothermia (low body temperature) and drowsiness.
What is the treatment?

An underactive thyroid can be successfully treated by taking daily hormone tablets to replace the hormones your thyroid gland isn’t making. The tablet is called levothyroxine. You will usually need the treatment for the rest of your life. With adequate treatment, you should lead a normal and healthy life.

You will initially have regular blood tests until the correct dose of levothyroxine is reached. Once you’re taking the correct dose, you’ll usually have a blood test once a year to monitor your hormone levels.

What are the side effects of levothyroxine?

This medication doesn’t usually have any side effects as the tablet is simply replacing the hormone your body is missing.

Side effects usually only occur if you’re taking too much levothyroxine. If this happens symptoms may include sweating, headaches, diarrhoea and vomiting.

How do I prevent an underactive thyroid?

There is no way of preventing an underactive thyroid.

What causes an underactive thyroid?
  • Autoimmune thyroiditis: An underactive thyroid often occurs when the immune system attacks the thyroid gland. This damages the thyroid gland which means it doesn't make enough hormone (thyroxine).
  • Caused by previous treatment to the thyroid gland: Underactive thyroid can also occur as a side effect or complication of previous treatment to the thyroid gland including surgery or radioactive iodine therapy.
  • Lack of iodine: Not common in the UK but common Worldwide is lack of dietary iodine. This is because the body needs iodine to make the hormone thyroxine

Other causes of an underactive thyroid include viral infections and some medications.

How do I find out if I have an underactive thyroid??

This at-home thyroid test helps you to test for underactive thyroid through a simple finger prick collection. If you’re found to have an underactive thyroid a conventional blood test may be required so that you can be started on the correct treatment.

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