Why TSH on blood tests?

[Fat_Sumo]

Why is it that everytime I have gotten my thyroid checked the doctor only asks for TSH? Why would he not test for T4 and T3 aslo?

Even if TSH is in the normal range couldn't you still have a problem with T4 to T3 conversion?

Also, there has been so many times where the doctor does not listen to what I want tested. I get the requisition form only to find out he has not checked off alot of the things I want to have tested.

I was thinking of just checking off the things that I wanted that the doctor did not check off, could this cause any kind of trouble or would they even realize it?

Thanks for the help
Fat_sumo

 

[11/2in22g5ccfilled]

yes, you would have a false reading,regular doctors don't know shit,get t2,t3,t4 checked to know what's what i mentioned prolactin to him and he said what's that have to do with anything,that's when i knew it was time
for a new doc,and the gen pop want to know why we self medicate!!

 

[Fat_Sumo]

^^

 

[xonic2xonic2]

Theres some great posts by DRJMW on blood tests.... I had similar question a few posts back...


Now T2 wtf is up with that, never heard of anyone testing it.

 

[11/2in22g5ccfilled]

yo, my bad not t2 just t3 t4

 

[Fat_Sumo]

Bump!

 

[Fonz]

Here you go, I wrote a post about this a year ago.

TSH (Thyroid stimulating hormone) stiimulates the thyroid to produce T3 and T4.

TSH is the MOST IMPORTANT indicator of thyroid function. Normal TSH levels are between (0.8 and 5.5). If your levels are lower < 0.8, your endogeneous thyroid production is just about zero.(When taking exogeneous oral T3 this is pretty common) If > 5.5, your thyroid is over-stimulated and produces vast amounts of T3 and T4, putting you in a hyper-thyroid state.

Anyways, if your TSH levels are within those boundaries(0.8 - 5.5), the thyroid produces T3 and T4(As its being stimulated by the TSH).

Problem 1: 80% of the metabolically active T3 in the blood comes from the
peripheral conversion of T3 from T4 via the de-iodinase enzyme
(cleaves off an iodine molecule). The other 20% T3 is left un-
bound in the bloodstream.

In MANY athletes, overtraining develops ESS in the training athlete. Euthroyd sick syndrome is just when the conversion of T4-T3 changes metabolically. So, now instead of being converted from T4 to T3, T4 gets converted to rT3(Reverse T3)(The molecular mirror image of T3), which is metabolically inactive. Result is low T3 levels, accompanied with weight gain and lethargy.

So, even tough your TSH and T4 levels are fine....your T3 levels are going to be low. You can test for rT3 buts its very expensive.

Anyways, there's many more intracacies to the thyroid, but thats a brief commentary on why you need a TSH test and the interaction between, T3, T4, and TSH.

 

[Fat_Sumo]

Here you go, I wrote a post about this a year ago.

TSH (Thyroid stimulating hormone) stiimulates the thyroid to produce T3 and T4.

TSH is the MOST IMPORTANT indicator of thyroid function. Normal TSH levels are between (0.8 and 5.5). If your levels are lower < 0.8, your endogeneous thyroid production is just about zero.(When taking exogeneous oral T3 this is pretty common) If > 5.5, your thyroid is over-stimulated and produces vast amounts of T3 and T4, putting you in a hyper-thyroid state.

Anyways, if your TSH levels are within those boundaries(0.8 - 5.5), the thyroid produces T3 and T4(As its being stimulated by the TSH).

Problem 1: 80% of the metabolically active T3 in the blood comes from the
peripheral conversion of T3 from T4 via the de-iodinase enzyme
(cleaves off an iodine molecule). The other 20% T3 is left un-
bound in the bloodstream.

In MANY athletes, overtraining develops ESS in the training athlete. Euthroyd sick syndrome is just when the conversion of T4-T3 changes metabolically. So, now instead of being converted from T4 to T3, T4 gets converted to rT3(Reverse T3)(The molecular mirror image of T3), which is metabolically inactive. Result is low T3 levels, accompanied with weight gain and lethargy.

So, even tough your TSH and T4 levels are fine....your T3 levels are going to be low. You can test for rT3 buts its very expensive.

Anyways, there's many more intracacies to the thyroid, but thats a brief commentary on why you need a TSH test and the interaction between, T3, T4, and TSH.

Thanks very much fonz for the response!
I just had my TSH checked and it came back 3.38!
What other thyroid tests should I ask for just so I can put my mind at ease?
Free t4 and t3?

Thanks again

 

[Fonz]

Thanks very much fonz for the response!
I just had my TSH checked and it came back 3.38!
What other thyroid tests should I ask for just so I can put my mind at ease?
Free t4 and t3?

Thanks again

Yes. If you have high Free T4 and low T3, then you are converting T4-T3 at a very low rate. Thats ESS.

If T4 and T3 come back in the normal range your thyroid is fine.

 

[Fat_Sumo]

Yes. If you have high Free T4 and low T3, then you are converting T4-T3 at a very low rate. Thats ESS.

If T4 and T3 come back in the normal range your thyroid is fine.

I guess I will have to go in and get that checked! Seems like these freakin doctors never test what I want them too!

 

[DrJMW]

Get free t3, free t4, and TSH checked to see your entire thyroid function

 

[Fat_Sumo]

Question drjmw:

If ask for specific tests do they have to test what I want? It seems like doctors, around here anyways, think that I am insulting there intelligence by asking for certain tests! It is really getting very frustrating!

Why would they not test complete thryoid function rather then TSH? Just doesn't make sense to me!

On my last thryoid check, which they only checked for TSH, my TSH levels came back as 3.38 with the high end of the normal range being 4.0! Do you think there could be a problem here as this level is in the high end of normal?

Thanks doc, always a pleasure reading your posts!

 

[Fonz]

Get free t3, free t4, and TSH checked to see your entire thyroid function

The free T3 test isn't offerred anymore. The thyroid package is TSH, Free T4, and T3.

You have to order it APART from the thyroid package(pain in the behind)