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Thyroid buying guide

Understand the different types of thyroid blood tests before purchasing.

Why buy a private thyroid blood test?

Thyroid conditions are common - an underactive thyroid is thought to affect 2.3 million people across the UK, or 3.6% of the population. If you are a woman, your risk of developing a thyroid condition is higher than for a man - this is because most thyroid conditions are caused by an autoimmune disorder (where your immune system attacks your own cells) and these are more prevalent in women than in men. Your thyroid governs your metabolism - too much thyroid hormone (hyperthyroidism) speeds things up causing symptoms like weight loss, feeling overly hot, fidgety and anxious, and too little (hypothyroidism) slows things down, leaving you exhausted, feeling cold and gaining weight or struggling to lose it. 

If you have symptoms then your doctor will normally test your thyroid hormones. However, the types of thyroid test available from your GP can be limited - they are often limited to thyroid stimulating hormone (TSH) and free thyroxine (FT4). Private thyroid tests give you access to the full range of thyroid hormones, thyroid antibodies and nutrients that can affect your thyroid health, together with the added advantage of a convenient and speedy service.

What are the different types of thyroid test?

1. Thyroid profiles and thyroid function tests

Most thyroid tests are bought as thyroid profiles which are specially curated panels of tests designed to provide deeper insight into your current thyroid function as well as to identify the reason why your thyroid may be overactive or underactive. Most thyroid profiles will test for thyroid stimulating hormone (TSH), together with either or both of the main thyroid hormones, thyroxine (T4) and triiodothyronine (T3) and may also include thyroid antibodies (thyroglobulin antibodies and thyroid peroxidase antibodies). 

2. Thyroid profiles with general health and nutrition

Sometimes it isn’t enough to just focus on thyroid function; this is especially true if you are trying to investigate symptoms which may be associated with an underactive thyroid, but could also be caused by other conditions such as iron deficiency anaemia, a nutritional deficiency or a hormone imbalance. For this reason, more advanced tests will include relevant health and nutritional biomarkers. Optimising certain vitamins and minerals can also support your thyroid function - so a thyroid profile which includes nutritional biomarkers like the B vitamins, ferritin and vitamin D, can help in the management of a thyroid condition.

3. Single biomarker tests

It is possible to buy tests for individual thyroid hormones and thyroid antibodies. These tests are usually bought to complement other tests that you may have taken already. For example, if you have had a thyroid test from your GP which didn’t test for thyroid antibodies then you may wish to test your antibodies separately to establish whether an autoimmune condition could be the cause of your thyroid condition. Testing thyroid hormones individually is generally not recommended unless it is done in tandem with other thyroid function tests as the interpretation of a single test in isolation may be limited.

How do I choose the right thyroid test for me?

If you suspect that you might have a thyroid disorder then the best way to investigate is by taking a thyroid blood test. We have 4 popular tests which can help you understand whether a thyroid disorder is causing your symptoms.

Thyroid Function Blood Test

This tests for thyroid stimulating hormone (TSH) and free thyroxine (FT4). This is a simple thyroid screening test which is sufficient to identify most cases of an over or underactive thyroid. This is the test that your doctor is most likely to perform if thyroid disease is suspected.

Why this test? You want a quick screening test to see if you may have a thyroid disorder.

Also for: people who are taking thyroid medication (e.g. levothyroxine) and are controlling their symptoms.

Thyroid Function Blood Test

This tests for thyroid stimulating hormone (TSH), free thyroxine (FT4) and free triiodothyronine (FT3). This is a more comprehensive test which also looks at FT3 - the biologically active form of FT4. This is the right test if you want a more in-depth look at your thyroid hormones.

Why this test? You want to investigate all your thyroid hormones including FT3.

Also for: people taking thyroid medication (including NDT and liothyronine) or who are still experiencing symptoms and want to check that T4 is converting to T3.

Thyroid Function with Antibodies Blood Test

This tests for thyroid stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3) as well as thyroid antibodies. If you have a family history of thyroid disease (or any autoimmune condition) then this is the right test to take. We will be able to tell you if your thyroid hormones are abnormal and whether this is caused by autoimmune disease (more likely if you have a family history). Even if your thyroid function is currently normal, elevated antibodies may increase your risk of developing a thyroid disorder in the future.

Why this test? For people who are concerned that they may have a thyroid condition and who have a family history of thyroid or autoimmune disease. 

Also for: people who are taking thyroid medication and want to monitor their thyroid hormones and antibodies.

Advanced Thyroid Function Blood Test

This test includes full thyroid hormones and thyroid antibodies as well as nutritional markers that can support thyroid function or, if they are low, can cause symptoms that are similar to a thyroid disorder. For example, low iron (ferritin), low vitamin D and low B vitamins can all cause fatigue and low energy.

Why this test? This is the best test to take if you want you want to pursue several lines of investigation for your symptoms. 

Also for: people who have been diagnosed with a thyroid disorder and want to make sure that they are getting important nutrients that support thyroid function.


References

 

1. Ingoe, L., Phipps, N., Armstrong, G., Rajagopal, A., Kamali, F., & Razvi, S. (2017). Prevalence of treated hypothyroidism in the community: Analysis from general practices in North-East England with implications for the United Kingdom. Clinical Endocrinology, 87(6), 860–864. https://doi.org/10.1111/cen.13440
2. Gleicher, N., & Barad, D. H. (2007). Gender as risk factor for autoimmune diseases. Journal of Autoimmunity, 28(1), 1–6. https://doi.org/10.1016/j.jaut.2006.12.004
3. Trivalle, C., Doucet, J., Chassagne, P., Landrin, I., Kadri, N., Menard, J.-F., & Bercoff, E. (1996). Differences in the Signs and Symptoms of Hyperthyroidism in Older and Younger Patients. Journal of the American Geriatrics Society, 44(1), 50–53. https://doi.org/10.1111/j.1532-5415.1996.tb05637.x
4. Canaris, G. J., Steiner, J. F., & Ridgway, E. C. (1997). Do traditional symptoms of hypothyroidism correlate with biochemical disease? Journal of General Internal Medicine, 12(9), 544–550. https://doi.org/10.1046/j.1525-1497.1997.07109.x