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Tg or anti Tg testing

amorriso
Posts: 186
Joined: Oct 2010

I need some help understanding the testing for the Tg or anti Tg. My doctors says i should go off my thyroxine before getting tested. Or I could take the thyrogen shots - if available by then. But he also said he could do the blood work while I was on the thyroxine, but it wouldnt be as an accurate picture. He's not doing it till November/December.

I need an expert to help explain this!

Cheers

Andrea

alapah's picture
alapah
Posts: 264
Joined: Oct 2009

What you're describing is not Tg/anti Tg but rather measuring your Tg levels under the influence of levothyroxine or not. Under the influence is called suppressed and without the levothyroxine (or on thyrogen) it's called stimulated Tg. I have also been told that stimulated Tg is more accurate but I have only had that a few times, while on thyrogen.

Anti Tg, if I get what you're saying, refers to thyroglobulin antibodies which not everyone has. There are specific tests to screen for that. If you do have TgAb it makes it more difficult to trust the Tg reading since the antibodies tend to mask the true level of the Tg.

Hope that helps somewhat. You can tell I am not a doctor!

amorriso
Posts: 186
Joined: Oct 2010

That helps a lot. Thanks. I prefer the non doctor advice - its much easier to understand!! :)

MarinMark
Posts: 145
Joined: Aug 2011

My TG level 5 days after a TT was 151. It that level too high or expected that soon after TT ???

The lab did it my mistake, as it is usually measured at least a month after surgery.

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alapah
Posts: 264
Joined: Oct 2009

MM,
did they measure your Tg before you had surgery? if so, comparison of the before and after might give some indication. i believe mine was done soon after surgery, but not 5 days after! still, before and after, i don't believe my numbers were in the three digits. that does seem highish to me though, for post TT = but, once again, i stress i am not a doc or expert on thyca. have you asked your doctor whether it seems high or what it might indicate, if anything?

as you go through this journey, you might want to keep in mind that it is a good idea to have your Tg labs run by the same lab, using the same assay, every time because this makes the samples/readings more comparable. the university of southern california has an advanced program that banks your previous samples and runs a control every time you send a new one. my doc sent my blood there prior to my TT and then every draw thereafter. i have also had a few labs done at Mayo Clinic and it's interesting to see that they are just slightly different (two draws taken fairly close together but done at different labs).

always is a very good idea to get copies of all of your labs and reports/doc notes for your own records. not that you can understand everything in there but it's helpful to try to gain an understanding and it makes it easier getting info to other docs if you ever want to go for a second opinion. i get copies of my films on disc as well.

MarinMark
Posts: 145
Joined: Aug 2011

think it's unusual to measure tg right after surgery and I haven't heard of anyone getting it measured before a total thyroid removal. I heard tg has a half life of over a month so that's why it is measured at least a month after surgery.

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