Thyroid UK
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Blood draw and medication

I'm having a full thyroid panel tmor afternoon as an add on to some other blood work. I don't really want to wait that late to take my Levo . If I take it first thing will it skew my results in any way? I had a Tsh done 3 weeks ago and my level had gone up to 1.7 - it's normally supressed at 0.1 with no hyper symptoms. I had been tinkering with my dose of 125mg and had reduced it by around 15 to 20mcg over the last 4 months to see if it reduced my hot flushes but just ended up feeling tired and hypo. For the last two weeks I've upped it to around 135mcg and feel much better. I know ideally I should have it tested in 8 weeks but I can only get a TSH at my gps and tmor I'm seeing a specialist so can get the whole lot done. will I see a true picture this quickly?

4 Replies

janiebell, you will skew the results if you take Levothyroxine before your blood test, take it after the blood draw. You won't feel the lack, it takes a week to absorb and metabolise a dose of Levothyroxine.

It takes 6-8 weeks after a dose adjustment to get a true picture of thyroid levels.


Yes, but won't the results be skewed anyway, by having it done in the afternoon? The TSH will be much lower than if it were done in the early morning.


GG, True, TSH will be lower in the afternoon than morning, but taking meds before the test will give false high FT4 and FT3.

1 like

Do not under any circumstances take your thyroid meds in the 24 hours before the blood draw


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