Navigating Hypothyroidism Diagnosis

Navigating Hypothyroidism Diagnosis

Being diagnosed with hypothyroidism is often no mean feat.  Getting diagnosed with hyperthyroidism is often done much more quickly because the symptoms are fairly easy to spot and start more suddenly than those of hypothyroidism which can come on very slowly and be attributed to other things such as working whilst running a home, going through the menopause etc.

Thyroid UK
Image from Thyroid UK​​

There are some issues with testing for hypothyroidism that can cause people to be ill for longer than is necessary.

One issue is whether or not you get tested to find out how much thyroxine your body is producing or whether you are converting your thyroxine into the active hormone, T3 (tri-iodothyronine).

Unfortunately in many areas of the UK, only the TSH (thyroid stimulating hormone) test is done, which is testing what the pituitary is producing and not what your thyroid is actually producing. 

The test for finding out what your thyroid is producing is called the free thyroxine test (FT4).  FT4 is actually a pro-hormone and is not an active hormone.  It needs to be converted in the body to T3.  The T3 hormone acts on the cells of the body and if it is low, then you could still have hypothyroidism even if the TSH and FT4 are within the normal range.

Just a quick note:  the higher the TSH level and the lower the FT4 level, the more hypothyroid you are – it’s like the opposite ends of a balancing scale. So, a high TSH and a low FT4 mean you are hypothyroid but a low TSH and a high FT4 mean you are hyperthyroid (overactive).

The TSH test is fairly good at detecting overt (full blown) hypothyroidism which is when the TSH level is well above the range.  The range for TSH is usually around 0.4 – 4.5 but some doctors will not start treatment for hypothyroidism until the TSH reaches 10 and some people can have a lot of hypothyroid symptoms at this point.

However, if the FT4 test is done at the same time, you can see whether the thyroid is producing enough thyroxine for your needs.  If the FT4 test is below the range and the TSH is above the range, you will be diagnosed as having hypothyroidism.  Often, though, the FT4 test is low within range but the TSH is still within range and you will not be diagnosed, even if you have symptoms.

The TSH can also be above the range and the FT4 low within range.  This is called “subclinical” hypothyroidism or “mild” hypothyroidism and you are likely not to receive treatment. You and your doctor will not know you have mild hypothyroidism if the FT4 test is not done.  It’s always a good idea to know if you have mild hypothyroidism as, if the cause is due to lack of good nutrition, this can sometimes be resolved.

A person can be subclinical for a long time before the TSH actually goes above the range but if an FT4 test is done and it shows low or low within range, your doctor may well offer a trial of levothyroxine.

There is a small group of thyroid patients who do not resolve all of their symptoms on levothyroxine because they do not convert their T4 to T3 very well.  The only way to find out if this is your issue is to have an FT3 test.

Unfortunately, though, many doctors and endocrinologists believe that FT3 is not as important as TSH for diagnosing hypothyroidism and therefore it is very difficult to get this test done on the NHS.

Even if your GP orders an FT3 test, in most cases the testing laboratory will return the test without the FT3 being done. Generally, only an endocrinologist will do an FT3 test although not always.

If you do have an FT3 test and it shows you are low, T3 can be given in tablet form (liothyronine).  However, the research that has been done so far is inconclusive, although in a lot of the studies, patients tended to prefer the addition of liothyronine to their levothyroxine.

Not every endocrinologist agrees with treatment with liothyronine, which is a shame, as there are many patients who still have unresolved symptoms on levothyroxine and have a very poor quality of life unless they take T3.

If you still have unresolved symptoms on levothyroxine, you will need to have a conversation with your GP about getting a referral to an endocrinologist (GPs cannot prescribe liothyronine anymore).  You will need to ensure that you find an endocrinologist who understands T3 treatment and who would be willing to give you a trial for at least 3 months.  New guidance is due to be published soon so this may change.

Because it is sometimes difficult to get an FT4 and/or an FT3 test on the NHS, the only option left is to obtain private testing.  We know that having to pay for private testing is not ideal for a lot of people but if you can afford it, it could change your life.

Having private testing done contributes to your own self care and you can feel more in control of your thyroid health.

Sometimes, taking a private test result to your doctor encourages them to repeat the test (just to make sure it’s correct).  This can then lead to a trial of either levothyroxine if you are subclinical or getting a referral to an endocrinologist.

Discuss private testing with your doctor first so that they are aware before you take your test results to them.  Be non-aggressive but firm in the discussion – an upset doctor will not help your cause.

You may even need to think about changing to a doctor who is up for working with you to become well again.

Thyroid UK works with Blue Horizon to enable people to access various tests, including thyroid testing.  It is a quick and easy process and can be done at home or in a clinic setting. You can also opt for their doctor’s comments which, will help you with your next steps.

Quick and Reliable

There's a reason that over 30% of Blue Horizon Kit requests are from patients that have used us before.