Underactive thyroid if blood tests "normal"?

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Is it possible to have an underactive thyroid despite blood tests coming back "normal"? I've had symptoms for quite some time that fit with hypothyroidism, though of course could well be down to something else. My main concern is lack of weight loss despite putting my (almost) all into trying.

I'm 45. I suffer from ME, which does rather complicate things. I tend to blame the ME for just about everything but I'm wondering if that's just been masking other issues.

For what it's worth, my blood test results were: Serum free T4 level: 8.2 pmol/L (range is 7.0 - 17.0)

Serum TSH level: 1.52mu/L (range is 0.40 - 4.50)

If anyone has any info/input on this, I'd be very grateful!

Thanks in advance

Hmmm very tricky. If you were going to think about conceiving and was Tsh 2.5, a consultant might advise taking some thyroxine.

The issue is you don't know if you have antibodies- if you have antibodies you might be going to deteriorate in the future. In which case it might be worth keeping an eye on symptoms/ retesting in future.

The thyroid is a complicated system involving other organs eg hypothalamus too. There can be issues with the pituitary causing secondary hypothyroidism. However on paper your results are 'normal' - there's a circadian rhythm for Tsh and t4. Possibly in the future (of health care) given your symptoms they might be classed other wise, but not currently.

The other thing you could look at is that you are getting the rda of selenium and iodine (not too much, the rda) to support the production of thyroid hormone- t4 is a pro hormone; the body used t3 (and t2, t1) but it needs to be converted from t4 to t3. Some t3 is made in the thyroid it's self.

On top of this - ferritin should be over 70/80 or a little higher, vit d good and b12 and folate good too.

My understanding of ME was that there are other systems/ issues at play?

On paper, it looks like your t4 is a tad low however. But as said we don't know your t3.

On that range, your FT4 needs to be at least 12. With results like yours, your doctor needs to be considering secondary hypothyroidism, where TSH looks good, but FT4 and FT3 are both low in range.

Do some research and then tackle your doctor. You may be able to overturn the ME diagnosis.

Thank you for your responses, Clarella and Mrstweedle.

I did notice on the printout of the results that there's no value for T3 - should this have been tested, or do they sometimes omit that one? These results are a few months old actually, so if I go back to the GP and request another test, should I state that I want my T3 levels to be tested too?

Just mulling it all over at the moment. Yes, it would be good to have something a bit more concrete that ME, something that can be dealt with. I've had ME for over 20 years though, so not sure my thyroid (if it is that) has been iffy for that long! Though who knows....

Again, thanks for your input, it's appreciated.

T3 is tricky as it varies during the day.
It's quite hard to get it tested as it isn't particularly helpful unless they are proving you have a conversion issue.

I feel it could be worth asking for a referral to an endo. Your t4 is pretty low.

Is there any auto immune disease in the family?

Look up all info on patient.co.uk and then read nice guidelines. There's a big british thyroid document listed in the references for the nice guidelines which might give more info.

Other than weight what other symptoms do you think you might have? I don't put on weight but at that level of t4 im very cold, dosy and pretty constipated.

www.gpnotebook.co.uk/simplepage.cfm?ID=x20110412164902938474

In your situation you need full testing, including FT3 to rule secondary hypothyroidism in or out. Most GPs don't know a lot about it, but it is more common than they think, and often missed because of over-reliance on TSH testing.

Your TSH does not match your FT4 so there is something going on.

If your FT3 tests low as well then you will know what it is.

I will look up that info, Clarella, thank you. No auto immune issues in the family that I am aware of. I will also request a referral to an endo.

My symptoms are coarse hair , which is also much finer and it's thinnned out a lot in recent years. I had put that down to being on the pill for a few months, but my hair has never recovered from that. Horribly dry skin, but again, I put that down to eczema! There's so many complicating factors it's hard to see the wood for the trees at times. Dreadful exhaustion, but again, attributed that to the ME. Definitely depression and severe anxiety, and huge cognitive difficulties. Concentration, memory etc shot to ribbons.

No problems with constipation or being particularly cold though.

Mrs Tweedie - have looked up secondary hypothyroidism, so will be perusing that too. I've been wondering recently about my adrenal function too. As a child I had severe eczema and very potent steroids were used on me, and I can't find any definitive information on whether that could have had a long term affect on my adrenals.

Thanks for the info - will be making an appointment with GP very soon.

Ah re steroids - I did have my cortisol response tested by an endo, though my issues were muscle loss. So it might be worth a referral as they deal with a range of other endocrine issues too.

He did ask about steroid use is what I mean.

Well, I saw the GP today, and she very happily agreed to test my thyroid again, but when I asked about testing the T3 levels, she said they don't test for that. She was very definite on that score, and told me the 'reason' why the don't test it (which I've forgotten now, but boiled down to it being "irrelevant"). I'm a bit miffed, as everything I've read points to it being quite relevant indeed.

Does anyone have any ideas on how/where I can get this tested please??

Oops, forgot about asking my GP for a referral to an endo. Will get the blood tests and then pursue that side of things...

It's very easy to get tests done privately and if you join one of the thyroid forums, you'll get discount from the major suppliers.

I use the ThyroidUK forum on www.healthunlocked.com.

That's good, will say that I'm not sure of many people who have borderline thyroid issues without constipation but I'm not a Dr or endo. And happy to be corrected. At 1.5 tsh I do noticably struggle.

This is the doc all the nice guidlines reference; it will explain the gps pov re t3

www.british-thyroid-association.org/info-for-patients/Docs/TFT_guideline_final_version_July_2006.pdf