# Does thyroglobulin go up after rai 131 ?



## Want2FeelGood

Saw this excellent inquiry in another forum. Within two months after radioactive I131 therapy, does the thyroglobulin elevate ?

Does anyone get their thyroglobulin checked within two months of I131 ? If so, what happened to you thyroglobulin level ?

Is it a bad or good sign if thyroglobulin goes a bit up right after I131 ?


----------



## Andros

Want2FeelGood said:


> Saw this excellent inquiry in another forum. Within two months after radioactive I131 therapy, does the thyroglobulin elevate ?
> 
> Does anyone get their thyroglobulin checked within two months of I131 ? If so, what happened to you thyroglobulin level ?
> 
> Is it a bad or good sign if thyroglobulin goes a bit up right after I131 ?


Are we talking Thyroglobulin or Thyroglobulin Ab?

Here is the whole story on both and how they are used to detect reocurrence or not.

http://labtestsonline.org/understanding/analytes/thyroglobulin/tab/test

The answer is yes it can if there are still cancer cells present and then there is the subject of false positive which you can read in the link provided.

Is yours elevated? Have you asked your doctor this question which I heartily recommend?


----------



## Want2FeelGood

Have read that before, but that article doesn't address the question of whether or not radioactive iodine 131 can cause a transient rise in thyroglobulin. (I'm not referring to the antibodies).


----------



## Octavia

I don't know the answer to your question, but since the RAI continues to work (and kill any remaining thyroid/cancer cells) for 6 to 12 months, I wouldn't agonize over it. You'll get a much more accurate reading several months after the RAI, versus 2 months after.


----------



## Andros

Want2FeelGood said:


> Have read that before, but that article doesn't address the question of whether or not radioactive iodine 131 can cause a transient rise in thyroglobulin. (I'm not referring to the antibodies).


administering
radioiodine to the patient which
must be weighed against uncertain benefits
in this situation, although such empiric I-
131 therapy often causes a decrease in thyroglobulin
levels, presumably reflecting a
cytocidal effect. Both F-18 FDG PET scan
(probably more sensitive after TSH stimulation)
and thyroid ultrasound may be
helpful in identifying thyroid cancer metastases
when the I-131 scan is negative
but the stimulated serum thyroglobulin is
elevated. Older data ..................continue below

http://interactive.snm.org/docs/Therapy of Thyroid Disease with Iodine-131 v2.0.pdf


----------

