Thyroid UK
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Underactive Thyroid Gland

Hi everyone

I suffer from all symptoms of underactive thyroid gland for almost 6 years, but at that time I was diagnosed with inflammatory Arthritis and spent all that time focusing on treatment for that. But then couple of years ago I was diagnosed with tumour in my neck (non cancerous) that need operation. I stopped my methotrexate treatment for arthritis over 6 months ago which made me more aware of the thyroid symptoms because I have very bad brain fog that made my focus very low and feeling heavy in my head, nausea and dizziness. I checked NHS website for my symptoms and few weeks back I did Thyroid Stimulating Hormones, T4, T3, and Cortisol blood tests in a private hospital as my GP was not considering doing it.

The results were:

The Thyroid Stimulating Hormone (TSH) is elevated and the free T4 level is low. The cortisol level is on the low side.

TSH - 4.490. Ref Range: 0.270-4.200

Free T4 - 11.89 : 12.0 - 22.0

Free T3 - 4.2 : 3.1 - 6.8

Cortisol - 159. : 166-507 Morning

Thyroid antibodies- Negative

I took the results to my GP and she booked me to do full blood tests because the private hospital used different reference ranges than NHS and to my surprise the results came normal! She said she can't refer me to Endocrinologist because the results are normal!

I read that NHS is using different reference range and that most people go to private consultants.

I don't understand how GP make serious decision on just blood tests ?

Does anyone have experience like mine in regards to conflicting blood tests ?



3 Replies

Yes, it is possible. The reason is that labs use different machines and the ranges can be different. That's why we always ask for the ranges when giving the results.

Your TSH is just above the range but unfortunately, for some unknown and unfathomable reasoning, the British Thyroid Association has decided that our TSH has to reach 10 before a diagnosis is given.

First, the blood test should always be at the very earliest. GPs usually go on the TSH alone and that drops throughout the day which may mean remaining undiagnosed, i.e. TSH high very early a.m. and lowers throughout the day.

Get a print-out of your latest results from the surgery, with the ranges, and post on a new question.

Blood tests should also be fasting, that's why we advise early morning testing as well and you can drink water. If you were taking thyroid hormones, you should allow 24 hours approx between the last dose and the test and take afterwards. Ask GP to test B12, Vit D, iron, ferritin and folate as we can be deficient.


Thanks Shaws for your reply. My gp did the B12, Vit D, Iron, Ferritin and Folate tests. I am getting a copy of the results in a couple of days and will post it then.

1 like

Usual advice on ALL thyroid tests, is to do early in morning, ideally before 9am. No food or drink beforehand (other than water) If you are taking Levo, then don't take it in 24 hours before (take straight after). This way your tests are always consistent, and it will show highest TSH, and as this is mainly all the medics decide dose on, best idea is to keep result as high as possible

You say GP aid results were "normal". ALWAYS make sure you get the actual figures from tests (including ranges - figures in brackets). You are entitled to copies of your own results.

If on NHS test the TSH result was anywhere within range your GP is likely to say it's "normal" even if it was right at top of range. Most people on levo need low TSH around one to be adequately treated.

ask for printed copy of the NHS test result, also ask GP to please check levels of vitamin d, b12, folate and ferratin. These all need to at good (not just average) levels for thyroid hormones (our own or replacement ones) to work in our cells


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