Thyroid Blood Test
Why take this test?
- you want to check symptoms of an underactive or overactive thyroid
- you want to test how well you are converting thyroxine (T4) into the more active thyroid hormone triiodothyronine (T3)
- you want to understand whether autoimmune disease could be the cause of a thyroid disorder
Thyroid conditions are very common but can be difficult to diagnose as many of the symptoms of a thyroid disorder can be overlooked (especially if they are mild) or confused with other conditions.
This test offers an affordable insight into what could be causing your symptoms by checking your levels of thyroid stimulating hormone (TSH), which is often abnormal in thyroid disease, free thyroxine (FT4) and free triiodothyronine (FT3). By measuring the amount of thyroid hormone that is "free" or unbound to carrier proteins in the blood, we can get a better picture of how much thyroid hormone is available to your cells.
Many thyroid disorders are caused by an autoimmune disease and your risk for this is raised if you or a family member has a history of autoimmune disease. This test looks for specific thyroid antibodies which can indicate that your thyroid is under attack from your immune system.
Thyroid Stimulating Hormone (TSH) is produced in the pituitary gland and stimulates the thyroid gland to produce thyroid hormones thyroxine (T4) and triiodothyronine (T3).
High levels of TSH indicate an underactive thyroid while low levels indicate an overactive thyroid. In primary pituitary failure, a low TSH will be associated with an underactive thyroid.
Thyroxine (T4) is one of two hormones produced by the thyroid gland. Most T4 is bound to carrier proteins in the blood. This test measures the level of T4 which is free, or unbound, circulating in your blood.
High levels of free thyroxine can indicate an overactive thyroid while low levels can indicate an underactive thyroid.
Triiodothyronine (T3) is one of two thyroid hormones produced by the thyroid gland. Most T3 is bound to protein in the blood. Free T3 measures the level of T3 that is free, or unbound to protein, and is available to regulate metabolism.
This test looks for antibodies to thyroglobulin, a protein which is specific to the thyroid gland. Under normal circumstances it does not enter the bloodstream, but if your thyroid is inflamed or under attack from the body's own immune system, then thyroglobulin can be secreted and antibodies detected.
Raised levels of thyroglobulin antibodies (TGAb) can indicate autoimmune thyroid disease.
Thyroid peroxidase is an enzyme which is produced in the thyroid gland and is important for converting T4 to the biologically active T3. This test looks for antibodies to thyroid peroxidase (TPOAb) in the blood which indicates that the body's immune system is attacking the thyroid gland and impairing its function.
Raised levels of thyroid peroxidase antibodies are often found in Hashimoto's disease (underactive thyroid) and can sometimes be detected before any symptoms are reported.
Raised levels are also found in over half the cases of Graves' disease (overactive thyroid)
All sample reports are for representational and educational purposes only. All data included in no way represents an actual patient. Any comparisons of results to actual patients, is completely incidental.
3 Working Days
How does it work?
Choose your test online, and you will receive your testing kit within 3 working days Not sure what you want? Let us know and we can help you. Just mail us firstname.lastname@example.org
How do I take a finger prick test?
Please check this link
And take a look at the guide enclosed with your kit.
How should I post my sample?
All our test kits come with a prepaid envelope and it’s very important you post it the very same morning you take your test, preferably before the midday post collection, to ensure we receive it the following day. We recommend you do your test Monday to Wednesday as weekend post can be problematic. If you're worried that you can't rely on the post in your region, we suggest sending it guaranteed next day delivery to ensure the sample arrives in good time.
I’ve received an e mail to say my test has failed. What should I do next?
Please e mail us at email@example.com, and we’ll speak to you directly to figure out what went wrong. We will provide you with a replacement test at a cover charge of £10.
Has my sample been received?
We normally send you an email to let you know we have received your sample. If for some reason this has not happened after 5 days of sending it, we will send you out a new one at no charge.
What if I’m struggling to fill the finger prick sample tube?
Please check this link
Where are my results?
Your results should be with you after 3 working days of posting your sample.
If not, please email us at firstname.lastname@example.org and we will check
My blood results are a little different to the ones I’ve had with my GP? Are they still valid?
There are a few reasons why this may vary, and quite simply diet, supplements, medications, dehydration to name but a few can be reasons for the difference.
On top of that, there are a few other more technical reasons such as
Pre-analytical variation; this relates to changes that may occur to the sample before it reaches the lab, for example temperature fluctuations during transport.
Are NHS tests more accurate than private blood tests?
All accredited laboratories are subject to the same strict rules and quality control procedures as one another and therefore NHS blood tests are not inherently more accurate than private tests, or vice versa. Very often NHS laboratories use the same laboratories as private testing, and all labs operate under strict regulation.
Can I trust a finger-prick blood test? And is it accurate?
Finger-prick samples have been proven to be as accurate as venous samples provided that the samples have been collected correctly and an adequate sample volume has been obtained.