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Can I Have Thyroxine Prior To TSH Blood Test?
Question: I have hypothyroidism and use thyroxine sodium 25mcg daily every morning as soon as I wake up.
I had done my last TSH test more than 6 months back. I plan to do my next TSH in a week or two.
My question is, when I go to give my blood sample for TSH blood test on fasting, should I take thyroxine sodium as usual before I give my blood sample? or should I consume thyroxine sodium after giving blood sample.
Also, I would like to understand how does thyroxine sodium work on my Thyroid gland. Does my daily dose of thyroxine sodium used by my Thyroid gland the same day? or does it work some other way?
I had done my last TSH test more than 6 months back. I plan to do my next TSH in a week or two.
My question is, when I go to give my blood sample for TSH blood test on fasting, should I take thyroxine sodium as usual before I give my blood sample? or should I consume thyroxine sodium after giving blood sample.
Also, I would like to understand how does thyroxine sodium work on my Thyroid gland. Does my daily dose of thyroxine sodium used by my Thyroid gland the same day? or does it work some other way?
Brief Answer:
replacement of thyroxine hormone.
Detailed Answer:
Dear XXXXXXX hi! welcome to HCM. your queries are very genuine.
1. thyroxine sodium is synthetic hormone, which your gland is not able to synthesize now so you are replacing it fromoutside in the form of tablet.
2. it is a very slow acting drug with a very long half life.
the message is it does not matter much if you take it the morning you are giving the sample , because it is a slow acting drug, so that morning dose will not make a difference.
another point , morning sample or empty stomach will not matter. for thyroid sample can be given any time of the day and any fed state.
as i told you thyroxine does not work on thyroid gland. it is a replacement molecule. thyroid gland does not require or take up thyroxine. it is supposed to make thyroxine and supply to the body for its metabolism. so it goes and starts acting in the body at end organ level. it builds slowly and the blood level is then maintained at any particular dose for every individual.
regards!
replacement of thyroxine hormone.
Detailed Answer:
Dear XXXXXXX hi! welcome to HCM. your queries are very genuine.
1. thyroxine sodium is synthetic hormone, which your gland is not able to synthesize now so you are replacing it fromoutside in the form of tablet.
2. it is a very slow acting drug with a very long half life.
the message is it does not matter much if you take it the morning you are giving the sample , because it is a slow acting drug, so that morning dose will not make a difference.
another point , morning sample or empty stomach will not matter. for thyroid sample can be given any time of the day and any fed state.
as i told you thyroxine does not work on thyroid gland. it is a replacement molecule. thyroid gland does not require or take up thyroxine. it is supposed to make thyroxine and supply to the body for its metabolism. so it goes and starts acting in the body at end organ level. it builds slowly and the blood level is then maintained at any particular dose for every individual.
regards!
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Above answer was peer-reviewed by :
Dr. Chakravarthy Mazumdar
Answered by
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