T3 to T4 ratio - how to calculate

[Monika_]

Hi, Could somebody help me please how to calculate T3 to T4 ratio? My FT3 was 4.31 (3.1-6.8) and FT4 was 15.5 (12-22) Additionaly TSH was 3.6 (0.27-4.2). It feels taht TSH was to high and the hormones were low? However the conversion possibly is not a problem?

[greygoose]

FT4 was 15.5 (12-22) 35.00%

FT3 was 4.31 (3.1-6.8) 32.70%

I don't know how to calculate ratios, nor do I want to, because I don't find it useful. But, I can give you a handy calculator that will give you percentages which is easier to understand:

thyroid.dopiaza.org/

Looking at the percentages shows that they are very close together, which means that your conversion is good. But, as the percentages are only in the 30s, you are very under-medicated. Most hypos feel well when their percentages are in the 70s.

[Monika_ in reply to greygoose]

Thank you very much! That is very helpful! Many thanks!

[SlowDragon Administrator]

Welcome to the forum

Are you currently diagnosed as hypothyroid and on replacement thyroid hormones, or trying to get diagnosed

See from your profile this may have got worse since cancer treatment?

Head, neck or breast cancer treatments can precipitate thyroid issues

For full Thyroid evaluation you need TSH, FT4 and FT3 tested

Also both TPO and TG thyroid antibodies tested at least once

Very important to test vitamin D, folate, ferritin and B12 at least once year minimum

About 90% of primary hypothyroidism is autoimmune thyroid disease, usually diagnosed by high thyroid antibodies

Autoimmune thyroid disease with goitre is Hashimoto’s

Autoimmune thyroid disease without goitre is Ord’s thyroiditis.

Both are autoimmune and generally called Hashimoto’s.

Low vitamin levels are extremely common when hypothyroid, especially with autoimmune thyroid disease

20% of autoimmune thyroid patients never have high thyroid antibodies and ultrasound scan of thyroid can get diagnosis

In U.K. medics hardly ever refer to autoimmune thyroid disease as Hashimoto’s (or Ord’s thyroiditis)

Recommended that all thyroid blood tests early morning, ideally just before 9am, only drink water between waking and test

This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip)

Private tests are available as NHS currently rarely tests Ft3 or all relevant vitamins

List of private testing options and money off codes

thyroiduk.org/getting-a-dia...

Medichecks Thyroid plus antibodies and vitamins

medichecks.com/products/adv...

Blue Horizon Thyroid Premium Gold includes antibodies, cortisol and vitamins

bluehorizonbloodtests.co.uk...

Only do private testing early Monday or Tuesday morning.

Link about thyroid blood tests

thyroiduk.org/getting-a-dia...

Link about Hashimoto’s

thyroiduk.org/hypothyroid-b...

Symptoms of hypothyroidism

thyroiduk.org/wp-content/up...

Tips on how to do DIY finger prick test

healthunlocked.com/thyroidu...

Medichecks and BH also offer private blood draw at clinic near you, or private nurse to your own home…..for an extra fee

[Monika_]

Thank you for your response!

My main problem is a goiter that is growing slowly but surely and I am trying to figure out how to optimise my thyroid health and get the proper diagnosis.

I did have antibodies tested and the result was negative. I will possibly test it again at some point to be sure. Alhough as you say % of Hashi patients never get antibodies.

The Endo does even want to look into function of my thyroid saying that my hormons are ''normal'' and there is no point to look into it.

However, it looks to me that I need a proper diagnosis as the hormons even if in range - are not too great. Those test results are from Medichecks. The Endocrinologist prescribed only TSH years ago and that was it.

I am taking vit D3-K2 regularly but will follow your advise to test for other vitamines and minerals - as well.

[pennyannie]

As for the conversion ratio when on T4 only thyroid hormone replacement :-

We generally feel best when our T4 is up in/towards the top quadrant of its range and the conversion ratio is said to be 1 / 3.50 - 4.50 T3/T4 - with most people feeling at their best when they come in this ratio at 4 or under.

So you simply divide the T3 result into the T4 result - providing both results are with the same assay measure - which they are above - and I'm getting your conversion coming in at around 3.60 showing good conversion.

[helvella Administrator Thyroid UK]

Yopu do not need to calculate anything! Just use this calculator (this is a pinned post):

Thyroid Blood Calculators - updated

healthunlocked.com/thyroidu...