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Thyroid UK
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Thyroid result showing borderline?

I'm slightly confused as I have not been diagnosed with a thyroid condition but have a lot of symptoms of it, then last year I went into hospital with my heart (SVT) and had bloods taken whilst in hospital. My thyroid showed borderline overactive so I have been 're tested it shows borderline underactive I am due to have a heart procedure for the SVT but have requested my thyroid be checked again before I proceed with it . Can anyone tell me what borderline means please? I didn't ask for the tsh levels which I wish I had now as this is really bugging me

14 Replies

its vital that you get the details of all tests as it rather sounds like you might have Hashimotos Autoimmune thyroid if results are swinging over and under

its vital that tests for

thyroid antibodies


free t4

free t3




vit d3

are all done as they are all interelated and must be optimum much though many doctors have no clue


Thank you


Shelleyw82, borderline overactive (hyperthyroid) means TSH was low with FT4 and FT3 within normal range. Borderline underactive (hypothyroid) means TSH was high with FT4 and FT3 within normal range.

Normal range is very broad so it's a good idea to ask for results and ranges to gauge the extent of thyroid dysfunction.

It's not uncommon to have transient hyperthyroidism before becoming hypothyroid. Autoimmune thyroid disease (Hashimoto's) can also cause swings between hyper and hypo-thyroidism.


I am not a medical professional and this information is not intended to be a substitute for medical guidance from your own doctor. Please check with your personal physician before applying any of these suggestions.

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Thank you for your reply I'm going to ask for exact results now in the morning & await the next blood results the thyroid is very confusing but I want it looking into before having a heart op I may not even actually need


The Thyroid is very connected to the performance of the heart - too much or too little thyroid hormone can cause fluctuations in the way the heart performs.

Do not rely on the Docs knowing everything - do as much research as you can. Cardiologists rarely talk to Endocrinologists to enable their knowledge to overlap. When you have your results - post them here in a new post - for people to comment.....

Make sure you also know the results of the tests mentioned by reallyfedup too. Low iron can also affect the heart .....


Hi I have found the paperwork from my cardiologist. It says *TSH level showing 0.02 although both FT4 & FT3 were within normal limits. He then took a further blood test which says TSH to be almost normalised at 4.8! I am really confused as is this normal? I have had another test done yesterday & am waiting on results of that one


...sorry - but do you have the actual results for the FT4 and FT3. Normal really is an opinion - I think when he says that - he means your results are in range. Sometimes it is where you are in the range that is important. So post the ranges with the results - as they do vary from lab to lab....

Lets hope your next results are OK - did they test for thyroid anti-bodies ? The TSH result can vary due to the time of day or foods consumed I have read....


There the only results on this letter I've phoned my consultant asking for exact results I am waiting for a call back


I had problems with sinus tachycardia for 2 or 3 years - heart rate would rise to 150 just turning over in bed sometimes, or just getting up and going downstairs would do it. I also had severe chest pain that went on for months.

In my case the problem was caused by extreme iron deficiency, caused by blood loss from the gut, and untreated "borderline" hypothyroidism (TSH over range, FT4 and FT3 were rock-bottom in the range).

My blood loss was caused by a large polyp. It was eventually found and fixed. But I still had the other problems - the iron deficiency to make up for, and the untreated hypothyroidism. My doctor was uninterested so I was forced to fix these things myself. It worked, my heart improved immensely, and I feel so much better than I did a few years ago.

I've never regretted taking my health into my own hands. I just wish I could do it for every health problem I have. I just need to find a way of performing DIY surgery... ;)

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I've had iron levels checked and there normal its just this thyroid businesses and not understanding it & drs seem disinterested but I am rapidly losing weight & always very hyper can't sit still or concentrate for long. I'm glad you got sorted :-) x


Like Marz said above, normal probably means your results were in the reference range. But where they are in the range makes a big difference to how you feel.

For example, if a result for ferritin (iron stores) is 14 or 80 or 149 and the reference range is (13 - 150), doctors are likely to describe all these levels as "normal". But the person with the result of 80 (i.e. approximately mid-range) is much more likely to feel well than the person with a result of 149 or 14.

I was told by my doctor that my ferritin was fine when it just scraped into the range. But I could hardly walk upstairs without getting close to blacking out.

I wouldn't be happy being told by a doctor that my levels of anything were fine. I would want to know the actual number and the reference range.

If you are having big swings in your thyroid levels then it suggests that you have autoimmune thyroid disease, as Clutter said above.

This means that you have antibodies which are attacking your thyroid and slowly destroying it. When cells in the thyroid are destroyed by antibodies then any thyroid hormone that was contained in those thyroid cells is released into the body, raising the levels of T4 and T3 that will be found on blood test. As T4 and T3 levels rise, TSH levels drop. If the antibody attack dies down, then the destruction of thyroid cells slows down, your T4 and T3 levels drop and your TSH rises.

Sadly, doctors these days put all their faith in the TSH level, and often don't measure Free T4, Free T3 and thyroid antibody levels. So you are left trying to decide on a course of action based on limited information.

You can pay for thyroid testing and find out more information for yourself. For more info, see this link :


The more antibodies you have the greater the swings of thyroid hormone levels you will have.

In order to feel better you need to damp down the antibody activity. This will extend the life of your thyroid, make you feel better, and will delay the onset of permanent hypothyroidism. It will also reduce the amount of time you feel hyperthyroid, with your heart going nuts.

To learn about how to reduce thyroid antibody numbers, this book gets good reviews :


The author has autoimmune thyroid disease. She has a website and a facebook page you may find helpful :



However, despite all this information, it may still have no bearing on your heart problems, and having surgery may still be your best idea. Nobody here can make the decision for you.


Well its now showing normal at 2.5? Very odd I asked for the other things you mentioned in posts but he Said you only need to know TSH level! So looking like heart procedure will be done slightly scared but is it normal for a thyroid to go up down then normal?


The TSH is a measure of the pituitary hormone, not actual Thyroid hormones.

Hashimotos is an autoimmune condition and patients report both sets of hyper/hypo symptoms as the thyroid 'splutters' & fails.

Doctors say 'normal' meaning 'in range' - what is 'normal' for one person is not necessary optimal. Please check that iron again (ferritin) - my daughter was diagnosed with SVTs and had low iron - much improved now, she was also Vit D deficient beforehand. Vitamins & minerals are important and low levels can affect thyroid function. Please insist on tests listed if you are unsure whether to proceed with surgery. You can ask for private tests or visit TUK for more info....


Jane (fellow sufferer - I am not in the medical profession)


Thank you for your advice your very helpful I think I will buy my own kits like you recommend as it does feel no one in medical profession is taking it into consideration and they are my results so surely I should be allowed to know other results than the TSH level its very frustrating


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