I have been on Levothyroxine for over 25 years for an under active thyroid my dosage ranging from 25 to 100 Mgs My last blood test read 0.68 and I feel quite strange. I am also now having a problem with the colour vision in one of my eyes which I am under the hospital for. As yet the cannot find a reason for this I don’t think this is to do with the thyroid
I have never had (to my knowledge ) a T3 or T4 test and don’t really understand how the readings work can someone please explain in layman term.
Thank you
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Dordy
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As you may be aware Thyroid Uk run this forum. If you look on their site there is a lot of info to help you, not only about your question but other things to help your thyroid work better. Shout out if anything you don’t understand.
TSH alone is not an indicator of thyroid status, contrary to what doctors appear to think. It's very unfortunately that doctors adjust dose purely on TSH result, this keeps many patients unwell.
TSH is a signal from the pituitary to the thyroid to produce thyroid hormone if it detects there's not enough, in which case the TSH would be high (as in hypothyroidism or undermedication).
Generally when we are optimally medicated TSH is low in range.
FT4 and FT3 are the thyroid hormones.
T4 (what we produce naturally or take as synthetic Levo) converts to T3.
T3 is the active hormone that every cell in our bodies need and it's low T3 that causes symptoms.
Measuring FT4 and FT3 are important as these tell us how much hormone we have, and from those results we can see if we are optimally medicated or undermedicated.
The aim of a hypo patient generally, when on Levo, is for TSH to be 1 or below or wherever it needs to be for FT4 and FT3 to be in the upper part of their reference ranges, if that is where you feel well.
Check out the articles on ThyroidUK's main website, work you way down the purple menu on the left hand side:
Thank you for your reply. I think I need to get all the readings even if I have to arrange myself. I don’t want to feel like this it affects so many parts of your well being
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 you have autoimmune thyroid disease (Hashimoto's) diagnosed by raised Thyroid antibodies
Do you know if you have high thyroid antibodies?
Recommended on here that all thyroid blood tests should ideally be done as early as possible in morning and before eating or drinking anything other than water .
Last dose of Levothyroxine 24 hours prior to blood test. (taking delayed dose immediately after blood draw).
This gives highest TSH, lowest FT4 and most consistent results. (Patient to patient tip, best not mentioned to GP or phlebotomist)
Is this how you do your tests?
Private tests are available. Thousands on here forced to do this as NHS often refuses to test FT3 or antibodies or all vitamins
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
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