Hi everyone, new here and hoping for some advice if possible.
I had loads of blood tests recently including thyroid and the Dr called to say my TSH level was too low at 0.2 but free T3 and free T4 were fine at 5.8 and 18.8.
The Dr said it is probably a lab error as the results are inexplainable but from what I have read here that doesn’t seem to be the case.
Any ideas would be more than welcome!
Funny how Dr never question a lab error for results that a patient may be concerned about!
I'm not qualified to comment on your results though I'm sure a knowledgeable person will answer your query soon.
Good luck.
Thanks for the such quick responses - the people on this forum are amazing!
So the low TSH means nothing with normal T3 and T4 then? And having low TSH wouldn’t cause any symptoms?
Thanks again
Wow! So my Dr really has no idea then. She said that if it is low when we retest after 3 months we will ‘pull a treatment plan together’.
Based on your messages it is quite scary to think of what any plan might consist of... gulp.
The plan probably consists of progressively reducing your dose in the hope that the TSH will rise. No, she has no idea.
Farracc is not currently diagnosed or on Thyroid hormones
No, I realised that afterwards. 
Funny you should say that because that’s exactly what my Doctor wanted to do today! 😭
They are never happier than when they're reducing doses! And, I think that's because they don't really understand what levo is. If you're taking some sort of drug, being able to reduce the dose is a good thing. But, levo isn't a drug, and you need to take what you need, not reduce it at all costs. They don't seem to understand that.
GreyGoose that’s a very good point! I couldn’t think of a good argument for staying on my current dose and really just waffled on like an idiot! I could hear myself talking rubbish and I just want to curl up and die! I’m absolutely useless when talking to Doctors. I think it’s because I don’t want to question their intelligence by disagreeing with what they say. I come across as hostile and aggressive and I really don’t mean to be. 😭
Not a lab error. The TSH is low because both fT3 and ft4 are towards the higher end of their reference intervals, fT3 in particular tends to stay mid-interval. Usually a low TSH indicates that there is a little too much thyroid hormone, although there are exceptional patients who need a low TSH.
If you are not being treated for a thyroid disorder I would just keep an eye out for signs and symptoms of hyperthyroidism (rapid heartbeat, fine hand tremor) or even hyopothyroidism if your hormone levels should fluctuate.
If you are being treated for hypothyroidism I would see if you can reduce your levothyroxine a touch, if it makes you worse stay on the same dose.
A low TSH is associated with bone loss and risk of atrial fibrillation but your TSH is so marginal I wouldn't worry about it. Assuming you have not been diagnosed with a thyroid condition I would disregard these results and not worry. If your condition changed in the future they could run another blood test which might be more conclusive one way or another.
Thank-you, really helpful.
I am not being treated for anything - this has just come out of the blue but I have been having some strange symptoms (increased urination frequency, tingling mouth, disrupted sleep patterns, intermittent joint pain).
Bone loss and atrial fibrillation sound pretty serious. Is there anything else I should be worried about or looking for? I have 3 young kids to provide for so hoping this isn’t going to be to severe...
Do any of my strange symptoms sound familiar?
A low TSH is not associated with bone loss and atrial fibrillation, consistant high FT3, as in Graves, is associated with them. Ask your doctor to test your antibodies.
greygoose, whilst it is the action of thyroid hormones that cause bone loss and atrial fibrillation most of the studies have established links with TSH, I'm sure you've seen them. Normally TSH is a good marker for overall thyroid hormone activity, the combined effects of T3 and T4, which is why the reseach looks at TSH. We know all too well that in some patients the link between TSH and thyroid hormone breaks down and TSH becomes an unreliable marker. However, in general the studies linking a suppressed TSH with bone loss and AF are valid for the majority of the population but not for a minority of patients who require high hormone levels to function normally.
Yes, but if you say it like that, it sounds as if it's the action of the TSH itself. And, I don't think it's ever useful to compare people with thyroid problems to euthyroid people. I don't think enough research has been done for you to state that the TSH is 'usually a good marker for overall thyroid hormone activity'. You really should be more careful how you explain things.
But, no, I haven't seen any studies that link TSH with bone loss and atrial fibrillation. I've only seen studies that say there is no link.
There are lots of studies of bone loss / fractures / cardiac problems and TSH but we need to be selective because many of the earlier ones included patients who may have had concurrent parathyroid problems or e.g. thyroid cancer patients who had their TSH suppressed to prevent future cancer. This study led by Graham Leese is well conducted academic.oup.com/jcem/artic... . As you can see it reveals that an elevated TSH is as bad as a suppressed TSH, not something you will hear from the average endocrinologist.
By definition an euthyroid person will not have a suppressed TSH. However, if we look at untreated subjects there are studies that show that patients with a suppressed TSH are subject to bone loss and cardiac problems.
We know that TSH is a good marker for thyroid hormone activity, not least because evolution did a good job. Experiments show that TSH responds to fT3 and fT4 and in the early stages of thyroid failure TSH rises to stimulate the thyroid and increase type-2 deiodinase to maintain stable fT3 levels. Unfortunately, this mechanism doesn't work in every patient. TSH is relied upon in some cases when it shouldn't be but in general it serves the majority of the population very well.
I didn't mean to imply the (lack of) action of TSH on bone and heart causes bone loss or AF. I said that TSH is a marker for thyroid hormone activity and there is an association between TSH and these conditions. In fact TSH does have a direct effect on bone formation, I've never studied this mechanism but my impression is that it is a minor effect and we can ignore it.
What, a low TSH when free t4 and free T3 are well within range? Most of those studies (AFAIK) don't even mention what the frees were, but concentrate on TSH or are about people with hyperthyroidism. My TSH is always low as I have a genetic defect in both TSH and TRH receptors. So am I going to get AF and osteoporosis even though my frees are quite low?
'Unfortunately, this mechanism doesn't work in every patient.' Your profile says you have secondary hypo, so your TSH does not reflect your thyroid status.
A genetic 'defect' in TSH and TRH receptors? Do you really mean defects causing congenital hypothyroidsm or just common polymorphisms which have little or no relevance? A 'defect' in TSH receptors would lead to very high TSH.
So you're saying it's not low TSH that causes AF etc (because if it was it wouldn't matter why TSH was low), but thyroid hormone level. Apparently I have a genetic problem with TRH receptors and also one with TSH stimulation. I keep being told that the TSH one should mean that I have high TSH,. but the TRH one means that my hypothalamus doesn't tell my pituitary to start producing, so the fact that it wouldn't know when to stop doesn't seem to register. Probaly are just common polymorphisms since no one seems to know why I have central hypo - plenty of bangs on the head but no severe blood loss.
Yes, it's not the TSH itself but the fact that TSH usually reflects overall thyroid hormone levels. Everyone has polymorphisms in the sense that our genes differ, we may have a polymorphism for brown or blue or green eyes. In a thyroid sense the various polymorphisms mean we have slightly different natural TSH or fT3 or fT4 levels and may have slightly different risks for various disorders. It may be that if the thyroid packs in certain polymorphisms may confer a disadvantage although for complex reasons I don't believe the DIO2 ones matter provided you get a little T3. I'm drifting too far from farranccc's post now.
If a TSH is low because the pituitary is not producing enough for whatever reason then the risk of bone loss and AF does not apply. If TSH is suppressed due to elevated fT3 and fT4 (even when in interval) then there are risks of bone loss and AF. These risks should not be ignored or exaggerated and balanced against the benefit of resolving hypothyroidism.
farranccc results suggest she might be beginning to become hyperthyroid, so it makes sense to monitor it in case it progresses. Even if hyperthyroidism is confirmed in a few months’ time it has been caught very early so any risks will be negligible.
my tsh was low and I was diagnosed with sub clinical hyperthyroidism, I thought the diagnosis was also based on signs and symptoms?
It should be, but rarely is. Doctors don't know anything about symptoms because they don't 'do' them in med school! Diagnosing hyperthyroidism - subclinical or otherwise - solely on the basis of a low TSH, is lazy and dangerous. The Frees and antibodies should also be tested. You could have Hashi's, or you could have Central hypo causing your low TSH. Even the man who invented the TSH test says that is should not be used alone for diagnosis, and never at all for dosing. 
Increased urination, reduced sleep requirements and joint pain CAN be associated with hyperthyrodism (overactive thyroid). I would perhaps ask your doctor to run another blood test in a month or two (TSH, fT3, fT4, TPO and TRAb antibodies).
Bone loss and atrial fibrillation risk are very much long term problems that occur after years of hormone excess so I wouldn't worry about them.
Sounds a sensible GP to leave alone and monitor rather than place undue reliance on a single test
Even though I have lots of symptoms? Hopefully the next test will be fine
You didn’t mention the symptoms ...
I did somewhere but there are a lot of posts now! Symptoms include;
- tiredness even after 8 hours sleep
- increased urination frequency
- tingling roof of mouth
- mild pain in many joints
- generally feeling weird
Most of the above come and go and I have a mixture of them on a day to day basis.
Do you have any sort of a diagnosis of thyroid problems? None of this is very clear. And being on thyroid hormone replacement or not, completely changes interpretation of blood tests. But, as I said above, you do need your antibodies tested.
What sort of symptoms do you have?
So you are not currently diagnosed as having a thyroid problem or on any thyroid medication at all?
For full Thyroid evaluation you need TSH, FT4, TT4, FT3 plus TPO and TG thyroid antibodi also very important to test vitamin D, folate, ferritin and B12
Low TSH and high FT4 and high FT3 can be due to Graves' disease or early stage Hashimoto's
Private tests are available. Thousands on here forced to do this as NHS often refuses to test FT3 or antibodies
thyroiduk.org.uk/tuk/testin...
Medichecks Thyroid plus ultra vitamin or Blue Horizon Thyroid plus eleven are the most popular choice. DIY finger prick test or option to pay extra for private blood draw. Both companies often have money off offers.
All thyroid tests should ideally be done as early as possible in morning and fasting. This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip, GP will be unaware)
To test for Graves GP or endocrinologist need to test TSI or TRab antibodies
If TPO or TG antibodies are high this is normally Hashimoto's, (also known by medics here in UK more commonly as autoimmune thyroid disease). Though Graves can also have high TPO or TG antibodies
About 90% of all hypothyroidism in Uk is due to Hashimoto's. Low vitamins are especially common with Hashimoto's and Graves . Food intolerances are very common too, especially gluten. So it's very important to get TPO and TG thyroid antibodies tested at least once .
Link about thyroid blood tests
thyroiduk.org/tuk/testing/t...
Link about antibodies and Hashimoto's
thyroiduk.org.uk/tuk/about_...
thyroiduk.org.uk/tuk/about_...
thyroiduk.org.uk/tuk/about_...
I always have low tsh. My endocrinologist who is a professor is never concerned with my low level. My tsh is the same number as yours
My TSH is always low, unreadable in fact. Never thought it could be a problem until my GP suddenly decided I needed a bone density scan. I was shocked to find I have osteoporosis which she believes is due to suppressed TSH. I was sent to an endocrinologist and he agrees! Currently I am trying to reduce my dose of thyroxine and get the TSH up a bit. There seems to be no other obvious cause of my bone loss.
I have to get a blood test in a few weeks before my next visit to the endo, he is testing for pretty well everything, just in case we can find an underlying cause for the osteo. Scary stuff indeed.
Did you have a fasting blood test as well, have they checked for diabetes regarding your increased urine?
Hi - I did have a fasting blood test and it appeared that I was having a hypoglycaemic episode as my glucose level was 2.4. I did several other tests including the hbc1a (?) and it appears it was a one off...
Any significance to thyroid issues?
Do you take B vitamins or a hair and nails supplement containing biotin? That gives false blood results.
I sometimes have a ‘handful’ of b12 vitamins as I thought they might help. I cannot remember if I had some when I had my blood test...
B12 is OK, it's biotin (in most B complex) and you need to stop it for a week before a blood test.
What effects does biotin have on bloods drawn, does it make them high or low?
Yes.
That is literally true - some results could be high; others low.
Depends on the type of assay used. For TSH usually low; for free T4 usually high (but it depends):
"biotin can skew the results to be either falsely high or falsely low. In the case of competitive immunoassays — usually used for low molecular weight targets (such as T4, T3, and cortisol) — biotin interference causes a falsely high result. In immunometric (sandwich) assays, it gives a falsely low result.
Other characteristics of the assay can also make a difference. For instance, a longer incubation time increases the opportunity for interference. Different assays for various analytes, even from the same manufacturer, can therefore vary in their susceptibility to biotin interference.
At the laboratory Mariash uses, the free T4 and total T3 assays use a biotin-streptavidin fluorescent detection system, so biotin can cause falsely elevated results, but the TSH and total T4 assays are not affected. In contrast, at Greenlee’s lab, biotin can lead to falsely low TSH results, but free T3 and free T4 tests are not affected. Biotin can also cause her lab’s assay for thyrotropin receptor antibodies (TRAb) to be falsely positive, which could lead to a misdiagnosis of Graves disease." From Endocrine news Jan 2016. See also nejm.org/doi/full/10.1056/N... for misdiagnosed Graves because of biotin.
I checked and it is B complex that I have been taking several of intermittently over the last few months (having read that some of my symptoms could be a B deficiency)
Does it the label say it contains vitamin B7 or Biotin (same thing)? If so, you need to get bloods done again, just in case, after stopping the supplement for a week.
Thank you all so much for your time and advice - it is really helpful and very much appreciated.
If, as suggested, that I might have sub clinical hypothyroidism would the symptoms be continuous or could they be intermittent day-to-day? Some days I feel ok and then others I feel awful.
Is there anything that I can do to help with feeling bad until I next see my Doctor? (i.e. avoiding food, more sleep, less stress, etc)
Less stress is always a good plan!
Low TSH
Low TSH
Low free T4 and free T3, normal TSH, low ferritin..
TSH low the rest normal
