Thyroid UK
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Trying to understand my recent thyroid blood test results

Can someone please tell me what my recent blood test for thyroid function, means?

I take 75mcg Levothyroxine daily.

Thyroid function:

Thyroid stimulating hormone 0.68 mIU/L 0.27 - 4.2

Free thyroxine 19.0 pmol/l 12.0 - 22.0

Total thyroxine (T4) 111 nmol/L 59 - 154

Free T3 4.0 pmol/L 3.1 - 6.8

Thyroid antibodies:

Thyroglobulin Antibody 16.7 IU/ml 0-115(Negative)

Method used for Anti-Tg: Roche Modular

Thyroid Peroxidase Antibodies 7.8 IU/ml 0-34

Method used for Anti-TPO: Roche Modular

4 Replies

Ihb3goto, Thyroid peroxidase and thyroglobulin antibodies are negative for autoimmune thyroid disease as your results are below 34 and 115 respectively.

TSH 0.68 is low in range and your FT4 19.0 is just shy of the top third of range which usually indicates adequate dosing. However, FT3 4.0 is low in range which means you are not converting well. If you are symptomatic a dose increase will raise FT4 which may effect better conversion and raise FT3, but it will suppress TSH.

Read Treatment Options in


Thank you for your helpful comments.


One of the first steps to think about is getting your vitamins and minerals up to optimum levels - particularly ferritin, vitamin B12, vitamin D, folate and, if you can get your doctor to agree, iron as well.

My conversion from T4 to T3 noticeably improved when I did this myself.


Thank you for your helpful comments.


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