T4 - how relevant in hypothyroidism?

[Claireinthecommunit]

My tests are due and my surgery will not include T4 “as a consultant from the local hospital has sent out a guidance note that it is not necessary to test it” - any comments?

[SeasideSusie Remembering]

Well if all they are testing is TSH then that wont tell them much. TSH is useful when diagnosing hypothyroidism, once on thyroid replacement it doesn't have much of a role.

TSH isn't a thyroid hormone, it's a signal from the pituitary gland to tell the thyroid gland to produce thyroxine if it detects there's not enough.

Once on thyroid replacement, it's important to know our thyroid hormone levels - FT4 and FT3 - that is going to tell us if we are optimally medicated, so once on hormone replacement then FT4 and FT3 are the most important tests.

This recent post by member Diogenes (Dr John Midgeley, scientist and advisor to ThyroidUK) a gem:

healthunlocked.com/thyroidu....

[Claireinthecommunit in reply to SeasideSusie]

Many thanks for responding. They are measuring T3 and TSH (plus vits at my request.). My last test (which was requested by the practice’s Clinical Pharmacist (who understood how the Thyroid worked/malfunctioned) included everything and full spectrum vits etc. This was via phone review of meds and I have since supplemented with Vit D oral spray, Vit B Complex and one containing zinc. My current This time my review is being done by a Practice Nurse who quoted the notice sent by a Grimsby Hospital Consultant saying no need to test T4. The PN also said that I have a very low TSH so they feel I am now being overmedicated. This floored me as having been wretched on 100 mg Levo for 2 years I was finally increased to 125 six months ago and am feeling much better-apart from hair loss. I cannot bear the thought of them putting me back on 100mg. I have read from papers posted on the Forum that some of us may well be stable on a very low TSH.

[SlowDragon Administrator in reply to Claireinthecommunit]

You need to stop any supplements that contain biotin, like vitamin B complex, a week before all blood tests, as Biotin can falsely affect test results

TSH is frequently suppressed when adequately treated.

Most important results are FT3 and FT4.

[Claireinthecommunit in reply to SlowDragon]

Thankyou Slowdragon for confirming T4 should be tested. I am taking the supplements you mention and am holding off having bloods done until its out of my system. Am going to ask to see the consultants guidelines which was apparently sent to the surgery saying no need to test T4 and taking along my own evidence (recommended academic papers/advice Ive downloaded from this Forum) and see what reaction I get.

[Claireinthecommunit in reply to SlowDragon]

To come back to Biotin affects (and Premarin) on tests, I would be interested to know in how the test is affected. Is it that TSH is raised or lowered or something else? Interestingly in recent conversation with my doctor he mentioned taking Biotin interfered but didn't know in what way. Thanks

[SlowDragon Administrator in reply to Claireinthecommunit]

Depends on test I think.....can be varied

endo.confex.com/endo/2016en...

endocrinenews.endocrine.org...

[pennyannie]

Sadly, it does seem to be the way things are going.

I am with Graves Disease, post RAI 2005 and became very unwell a few years back.

After being refused a trial of T3 last year, because of a suppressed TSH, I decided to trial both T3 and NDT myself.

I notified both the endo and my doctor of my decision and that I was happy to continue with the yearly blood test ritual providing I was to be monitored on T3 and T4 blood tests, and not solely on a TSH blood test.

Needless to say I haven't had an acknowledgement from either.

[Claireinthecommunit in reply to pennyannie]

Thanks for replying and I am seriously considering a similar action plan if they keep ignoring my symptoms and telling me ‘The computer says No!’

[SlowDragon Administrator]

Just testing TSH on any replacement thyroid hormones is completely inadequate

For full Thyroid evaluation you need TSH, FT4 and FT3 plus both TPO and TG thyroid antibodies tested. Also extremely important to test vitamin D, folate, ferritin and B12

Low vitamin levels are extremely common, especially if Thyroid antibodies are raised

Recommended on here that all thyroid blood 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, best not mentioned to GP or phlebotomist)

Last Levothyroxine dose should be 24 hours prior to test, (taking delayed dose immediately after blood draw).

Private tests are available. Thousands on here forced to do this as NHS often refuses to test FT3 or antibodies or all vitamins

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 special offers, Medichecks usually have offers on Thursdays, Blue Horizon its more random

If antibodies are high this is Hashimoto's, (also known by medics here in UK more commonly as autoimmune thyroid disease).

About 90% of all hypothyroidism in Uk is due to Hashimoto's.

Low vitamins are especially common with Hashimoto's. Food intolerances are very common too, especially gluten. So it's 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_...

List of hypothyroid symptoms

thyroiduk.org.uk/tuk/about_...

The aim of Levothyroxine is to increase the dose slowly in 25mcg steps upwards until TSH is under 2 (many need TSH under one) and FT4 in top third of range and FT3 at least half way in range

All four vitamins need to be regularly tested and frequently need supplementing to maintain optimal levels

NHS guidelines on Levothyroxine including that most patients eventually need somewhere between 100mcg and 200mcg Levothyroxine.

nhs.uk/medicines/levothyrox...

[Claireinthecommunit in reply to SlowDragon]

Many thanks for advice and link and its worth repeating that the moral and technical support from this Forum is hugely appreciated.