Thyroid UK

Blood Test Fasting Advice

Hi All,

Hope your first week after Christmas hasn't been too bad.

Can I please ask some advice?

I have just booked in for a full thyroid blood test for 7.15am Tuesday 16th Jan...... I'm only on 25mg levothyroxiene (was diagnosed around 18 months ago), when shall I take my last tablet before the blood test please?

I'd ask the doctor but they are just leaving a blood form on reception for me to collect.

PS: Will a nutrient test be included in the thyroid test or do I have to ask seperatly for this (excuse my ignorance).

Many thanks for any advice.

4 Replies


You need to leave at least 24hrs between when you take your last tablet and your blood test. That said I normally leave 48hrs.

Hope this helps



I thought it was that - many thanks.

You can drink water though right?



But only water.


Thank you Tanngales

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