11 doctors weighed in:
What does thyroxine total blood test tells a doctor about the patient?
11 doctors weighed in

Dr. Melissa Young
Internal Medicine - Endocrinology
6 doctors agree
In brief: Not much
Thyroid hormones like thyroxine float around partly bound to proteins and partly "free".
Only the free portion is active. In someone with a normal thyroid, the more protein that is present, the more thyroxine gets stuck, the more thyroxine produced so that the free portion stays normal. So the total goes up, but the free thyroxine is normal. Pregnancy and birth control can make the protein go up.

In brief: Not much
Thyroid hormones like thyroxine float around partly bound to proteins and partly "free".
Only the free portion is active. In someone with a normal thyroid, the more protein that is present, the more thyroxine gets stuck, the more thyroxine produced so that the free portion stays normal. So the total goes up, but the free thyroxine is normal. Pregnancy and birth control can make the protein go up.
Dr. Melissa Young
Dr. Melissa Young
Thank
Dr. Michio Abe
Internal Medicine
5 doctors agree
In brief: Total thyroxine
By itself, total thyroxine is not very useful.
As with any other lab value, total thyroxine level must be correlated with clinical findings. Tsh and free T4 may be more helpful if you are suspecting hypothyroidism for example.

In brief: Total thyroxine
By itself, total thyroxine is not very useful.
As with any other lab value, total thyroxine level must be correlated with clinical findings. Tsh and free T4 may be more helpful if you are suspecting hypothyroidism for example.
Dr. Michio Abe
Dr. Michio Abe
Thank
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