Thyroid UK
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Thyroxine Level Reported being High at 27

Hi I recevied a letter yesterday from my GP He received a letter from the rheumatologist that I attended a few weeks re Sojgrens diagnoise. She said my thyroixine level is too high at 27 I am only statring to feel better now since i found out that the my milk/ yougart I was having for my breakfast could stop me getting the full benift of the thyroixine I dont understand how the results were high I also wish Doctors would stick to there own fields Any advice thanks

1 Reply

Hi Twinkle,

It’s difficult to say precisely whether 27 is too high for your thyroxine level without knowing the reference range for your test. One test range might be 8 to 18 for example so a level of 27 would be way over range, but another range might be 12 to 25 and a level of 27 might be acceptable in that case.

See pages 25 & 26:

“The lack of thyroidal production of T4 and T3 along with the dependence on

peripheral conversion of T4 to T3 significantly alters thyroid hormone status in

patients on replacement therapy such that the ratio of T4 to T3 is increased.. FT4

concentrations may exceed euthyroid reference ranges in patients on thyroxine when

the TSH is normal whereas FT3 remains closer to euthyroid reference ranges.”

Another thing to consider is when you took your thyroxine in relation to your blood test. Thyroxine peaks in the blood for some hours after taking it so it’s possible that this could have led to an artificially raised level for you. I always get my thyroid test done first thing in the morning and take my thyroid meds after the test that day (I normally take them when I wake up) so as to eliminate as many variables as possible. The same applies to TSH, this varies over the day, being highest early in the morning, so that is another reason to get tested at the same time each day.

If you are concerned that your doctor might reduce your thyroxine then tell him how much better you are feeling and ask if you can have another test first before making any changes to your dose.


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