GP blood tests

[Edso57]

After much persuasion my GP has finally agreed to test FT4 and not just TSH. He’s also agreed to do an antibodies test too.

He is still insisting that if there was something wrong with either my FT4 levels or if I had antibodies, the TSH would *always* be high / increased and so these tests are “not necessary “.

Confused !!

[greygoose]

So is he. He just doesn't know much about thyroid. If you had Hashi's, your TSH would fluctuate a lot. Bet he doesn't know that TSH fluctuate throughout the day, either! And, if you had Central Hypo, both your FT4 and your TSH could be low.

[Edso57 in reply to greygoose]

Yes, the last time I went for a TSH test I was told early morning test / fasting wasn’t necessary! I specifically mentioned the possibility of central hypothyroidism but he said if I had that my TSH would be high !!

Sigh …..

[greygoose in reply to Edso57]

Oh dear! He really is ignorant. Mind you, very few doctors have even heard of Central Hypo, so I suppose that's not surprising. He just doesn't know what it is.

[SlowDragon Administrator]

Looking at previous posts

You have low B12, have B12 injections, take daily vitamin B coeliac and vitamin D

Remember to stop taking vitamin B complex a week before all blood tests as it contains biotin and biotin can falsely affect test results

GP needs to test iron and ferritin, plus TSH, Ft4 and Ft3 and TPO and TG antibodies

You need to test vitamin D twice year when supplementing

NHS easy postal kit vitamin D test £29 via

vitamindtest.org.uk

[Edso57 in reply to SlowDragon]

Thanks I will stop taking the vitamin B supplements a week before the blood test

[shaws Administrator in reply to Edso57]

Before suppkementing with B12 you have to have a blood test that excludes pernicious anaemia - another autoimmune condtion, If you do have P.A, you have to have to have a quarterly injection.

I have P.A. as did my mother. Due to her doctor telling her she needed no more injections both myself and sister thought that 'was good'.

Unfortunately, due to having her injections 'stopped' she developed stomach cancer.

I get a monthly injection of B12. My GP told me I could have as many as I want.

[SlowDragon Administrator in reply to Edso57]

You could consider taking a separate folate supplement in week before test

[Edso57 in reply to SlowDragon]

Thanks for the detailed replies and suggestions but we seem to have gone slightly off-topic here …..

My original question asked if it were possible to have normal TSH with either Central hypothyroidism or Hashimoto’s? GP is insisting that with either of those conditions TSH would *always* be raised above normal ?! I disagreed and insisted that FT4 and antibodies be tested ….

[SlowDragon Administrator in reply to Edso57]

With central hypothyroidism TSH would almost always be below 2

Low vitamin levels tend to lower TSH as well

[Edso57 in reply to SlowDragon]

Thanks, my last TSH was 0.38 (range 0.27 to 4.2).

[tattybogle in reply to Edso57]

" Low (below range) TSH with Low (below range) fT4 " is what GP's guidelines and training tell them indicates Central or Secondary hypothyroidism. So they are unlikely to consider it while TSH is within normal range.

But if they read the guidelines/ research properly they might understand that 'low normal' (very low but still within range) TSH can also be considered , IF fT4 is also unexpectedly low . Some of them won't agree with this idea though, so it will be hard to find one willing to investigate further if TSH and fT4 are both within range.

So Yes , your GP is obviously mistaken about 'high' TSH for central hypo, that's just illogical/impossible . By definition , the cause of central hypothyroidism is "not enough TSH production" (for whatever reason)

For hashimoto's hypothyroidism , as far as NHS are concerned , then a high TSH is always present, (or at least 'high normal' in the early stages)

So he's basically right about that one , ( sometimes hashimoto's does start off with a period of "too much thyroid hormone" a period of mild hypErthyroid caused by thyroid dumping T4 into blood from damaged thyroid cells , so because of this you do sometime see low TSH/high fT4 in early hashimoto's , or when thyroid is damaged further as time goes on )

The antibodies , TPOab (and TGab ).. these have nothing to do with Central hypo , (central hypo is not caused by destruction of thyroid tissue , it is due to a pituitary or hypothalamus problem)

But TPOab can confirm if "High TSH with Normal fT4 " is caused by early stages of autoimmune thyroid damage. So he's correct about that too , NHS do not test these until TSH is over range.

But you can test them yourself if you want to know for sure.

[Edso57 in reply to tattybogle]

Thanks that’s very helpful. 👍😀 Just a thought - if I had Hashimoto’s and my thyroid was starting to struggle AND I had central hypothyroidism, am I right in thinking there would be no significant increase in TSH?

[tattybogle in reply to Edso57]

Yes , (but you'll struggle to find a GP willing to consider that possibility )

They would assume that if you already had central hypo (before developing Hashi's ) then your TSH would already be 'low' with corresponding low FT4. (and also that you would have other symptoms related to low levels of the other pituitaty /hypothalmus hormones )

i suppose , if someone who already had 'a degree' of central hypothyroidism, but not bad enough for TSH to be very low., and they later developed hashimoto's (leading to even lower fT4 ), then their TSH would still be unable to rise , due to whatever reason was causing the original issue of 'not enough TSH production'

If it was the other way round and they had hashi's first and nobody diagnosed it , and then later developed central (pituitary/ hypothalamus issues) you would also get 'not enough TSH ' .... both scenarios prove the need to test for fT4 not just TSH.

Unfortunately .. all the NHS info tells GP's that central hypo is very very rare.

So in reality if they see a patient with normal TSH, it's difficult to get them to see past that. (unless you also walk in with some glaringly obvious signs of the other pituitary /hypothalamus hormones being deficient )

But, yes , the policy of only testing TSH, does have this major failing , in that it can occasionally miss Central hypo if fT4 isn't looked at too.

[Edso57 in reply to tattybogle]

Thanks for another detailed explanation- I’m pleased to say after going back to my GP after just a test of my TSH (and nothing else), he is now doing FT4, antibodies (and an ultrasound of my thyroid for good measure!). As he’s said, he’s doing this to draw a line under things……

[tattybogle in reply to Edso57]

I know the NHS, like the rest of us, need to avoid the costs of unnecessary testing... but it would be interesting to see a comparison of the costs for :

"one TSH /fT4/TPOab test"

~ versus the costs of ~

"one TSH test + several GP appointments to argue about it + another inevitable TSH along with the requested fT4 and TPOab test"

[Edso57 in reply to tattybogle]

My thoughts exactly!

[SlowDragon Administrator in reply to Edso57]

Many Hashimoto’s patients have a poorly/sluggish TSH…in that TSH should be much quicker to respond than it is

Perhaps in part because vitamin levels are often low, but also if thyroid levels are changing too much daily or even hourly TSH gets confused and doesn’t respond correctly…..

But don’t expect any medic to recognise this as a problem

Getting full thyroid including both antibodies and vitamins and cortisol levels tested will give better picture

[Edso57 in reply to SlowDragon]

I see ….. thank you !