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TEST INTERPRETATION

Here is a good site to see the test interpretation of many medical tests: http://www.neosoft.com/~uthman/lab_test.html

Subj: Re: [hyperthyroidism] T3 question for Elaine & others
Date: 11/2/00 2:14:05 PM Pacific Standard Time
From: Mooredaisyelaine@aol.com
Reply-to: hyperthyroidism@egroups.com
To: hyperthyroidism@egroups.com


< QUESTIONS:

1. You wrote, "You're right about T3 Uptake and T4 not being as
worthwhile as an FT3". Did you mean FT3 or FT4? If FT3, is that the urine test, triiodothyronine test, or something totally different?

I meant both actually. the free hormone levels give you a better idea of what's going on. You'd want blood tests for these levels because it's the amount in your blood that is available to act with cells throughout the body that is important. Different cells throughout your body have thyroid hormone receptors. The free thyroid hormone goes to these receptors and activates them, causing the symptoms you associate with thyroid hormone, like heat and energy production. These binding proteins, by the way, carry both T4 and T3 throughout the body.

2. From what you said, and given my current thyroid levels, there
would seem no need for me to continue getting a T3 Uptake __X__true or
_____false? 

Now that we have tests to measure FT4 and FT3, there's no real 
need for the uptake. If a problem with binding proteins is suspected, docs sooner order a Thyroid binding Globulin (TBG) test.

3. Even though obsolete, I plan to continue getting a Total T4 and
maybe the Free Thyroxine Index because I have results on those 2 tests going back to 1992 and 1988. I thought I might try to get my levels back to what they were then. Does this make sense to you__Not really_____? I do not 
have TSH orFree T4 results from my pre hyperT days.

Zoey, I see your logic, but to be honest these aren't the best of tests. The lab reference manuals don't even mention these tests anymore. Once we were able to do accurate tests for TSH and free hormone levels, those tests weren't needed as much. 

4. The Free thyroxine index is a calculation we used to do before the 
FT4 test came out on the market. By measuring serum total T4 and the T3uptake we were able to figure out how much of the free T4 was bound and how much was free, so it was sort of a "guestimation" of how much FT4 was available. The FT7 was ordered when docs wanted both a T3 and T4, and then we added some kind of calculation in, which none of my lab books even mention anymore.

5. Any suggestions about how high I might let my FT4 go before being concerned?

You can safely go up to the high end of normal which is usually 
about 2.4.

6. What, if anything do you know/think about Welbutrin? As much as I
hate drugs, I was considering taking it to get out of my zombie like
lethargy. Any suggestions or opinions? I remember it from working in toxicology, and it is one of the better drugs out. Originally, it was for anxiety. I don't know if it will help with the energy issue.

My PDR mentions that it's an antidepressant, but not related to the 
tricyclics. It says a substantial proportion of patients treated with Wellbutrin experience some degree of increased restlessness, agitation, anxiety and insomnia, especially shortly after initiation of treatment. It goes on to say that some of these patients then required sedatives. Considering how sensitive you are to drugs, I don't think this is what you need. Would your insurance pay for one of those top notch profiles that measure all your minerals and vitamins? I know Life Extension has this service for blood tests, and John's site iThyroid has some places for hair analyses.

Or could you perhaps ask your doc for a sample of Wellbutrin to just try it out? For some reason, though, what you describe sounds more like you need more thyroid hormone or some mineral or vitamin that you're deficient in. Have you had a CBC? Could you be anemic? 
Did you ask about having those other antibodies run? 

Subj: Re: [hyperthyroidism] Re: T3 question for Elaine & others
Date: 11/3/00 2:36:55 PM Pacific Standard Time
From: Mooredaisyelaine@aol.com
Reply-to: hyperthyroidism@egroups.com
To: hyperthyroidism@egroups.com


Chris, here are the answers to your questions:

1. Is the T-3 Uptake essentially a count of the proteins that bind up 
T-4 hormone, or both T-4 and T-3? 

These proteins bind with both T4 and T3.

2. Is the Free T-3 measure a more accurate way of telling if your 
thyroid levels are high or low? How much attention should we pay to 
the Free T-4 counts?

Chris, although in the last year or two much hoopla has been made of T3's great powers, T4 (rather FT4) is very important. In fact, I wrote Dr.DeGroot about this and he verified that the brain and hypothalamus require FRESH T3 converted from T4 right on site. That's why you wouldn't want to use T3 alone. They're equally important as far as I'm concerned, and so probably are T1 and T2 and T0, the little hormone precursors we don't hear that much 
about. That's why I'm sticking with Armour. Recent studies show that T2 is needed to produce the enzyme which converts T4 into T3.

3. I've heard that T-3 is the active hormone, and it is made from the 
T-4, which I've heard called a "prehormone." Isn't (free) T-4 active? 

Yes, it's active as I've described above. In a sense, it is a prehormone, but that's not all it is.

4. Do both T-4 and T-3 activate thyroid cell receptors? Are these 
the same as TSH receptors? 

There are lots of different thyroid receptors, and there are actually two types of TSH, an alpha and a beta portion. There are specific receptors in different body parts, depending on what's needed. It's all rather elaborate. Cells throughout the body have receptors for thyroid hormone, T4 and T3. Cells in the thyroid, hypothalamus, salivary glands, spinal column and a few other places have receptors for TSH. Thryoid hormone, they're finding, isn't only made in the thyroid gland although the vast majority is made there. That's why people without thyroids can still make a little hormone. But only a little.

5. What is the difference between TSI - Thyroid Stimulating 
Immunoglobulins, and TBI - Thyroid Binding Immunoglobulins. Are these the "proteins" that, in effect, carry the thyroid hormones (T-4 and T-3), and meet up with the receptors?

No, these aren't the proteins that carry thyroid hormone. Those are TBG, albumin, prealbumin and transthryetin. The proteins in antibodies are made out of a different type of protein known as an immunoglobulin, specifically the G class or IgG for thyroid antibodies.
TSI are actually TBI and, depending on the lab, your result for TBI includes both TSI and TSH blocking antibodies. 

Think of it this way. TSH from the pituitary stimulates receptors in your thyroid (mainly) causing it to produce more thyroid hormone. These receptors are little off-on switches on the cell surface. Stimulating antibodies bind to this receptor and stimulate it just like TSH would. 

Binding antibodies include TSI and also blocking antibodies which bind to the receptor, getting in the way of TSH and causing hypothyroidism. It's also thought that some binding antibodies just hang around at the receptor site doing nothing. Also, on each cell there are lots of different receptor binding sites. Some, only TSH can bind with and some these antibodies can bind with. And in another group of binding receptor sites, both antibodies and TSH can bind. 

There's a lot of variation going on here, and this is the reason people with high blocking antibodies become hypothyroid but not absolutely. There's also some hormone being produced unless you reach complete thyroid failure.

Hope this helps. It really does get confusing. A lot of this confusion results from early studies and early tests. They used to think there was just one antibody.