Is there a time when TOTALS are assessed?

Hi All,

Regarding total t4 and total t3, not to be confused with their FREE counterparts, is there a way to analyze them for better thyroid treatment? They have to be useful numbers, yeah? Are they relevant in comparison to FREES?

For instance, would someone with a lower total have less med for a higher FREE? I'm just making up numbers but let's say the patients total t4 is 100 and her free is 30. Take another patient whose total is 80 and his free is 30. Would the patient with a smaller total be less symptomatic/ill than the patient with a higher total?

Does that make sense?

THANKS FOR ALL INPUT. Trying to learn how to better assess my labs, symptoms, and treatment.

Always Grateful,


7 Replies

Total T4 and T3 are much inferior to the free hormone measurements. This is because the free hormones are those levels that actually enter cells. The totals are measures of the T4 and T3 reservoirs that are attached to circulating proteins in blood, which release free hormones as required. The size of reservoirs in individuals can vary enormously. Some people have none of the chief binding proteins at all, and others have 4 times the average. The amount of T4 and T3 bound on varies with these protein levels. People with none of the important protein have very low reservoirs and with high, have big reservoirs. So, the same free T4 and free T3 could be got from different people with a 12 fold different amount of T4 and T3 bound on to the protein.

Thank you diogenes. Do you know what those proteins are called? I ask because your explanation makes me wonder whether someone with too few proteins can improve them, and thereby improve the binding of FREE t4 and or free t3.

The main one is called thyroxine binding globulin (TBG). In an average person it s reservoir takes up about 60-70% of the total T4 and T3. Two others are more minor: transthy retin takes yp about 20% of T4 and virtually nothing of T3, and albumin takes up about 10-15% each of both. You can do nothing to change the amounts except to get pregnant or very ill.

Ohhhh I have seen and heard of them on my lab reports, but never knew that they were proteins. Thank you so much for your kind replies and helpful explanations. Even though I don't feel well, I feel stronger knowing more about what's happening.

Thank you. 😊

No, they wouldn't be less symptomatic in that case.

Total T3 is Free T3 plus bound T3. The bound T3 is inaccessible to the body. You can only use Free T3. And, it's low Free T3 in the cells that causes symptoms. The bound T3 just floats around in the blood until it becomes Free (unbound) - whenever that is.

Ahhh. I understand. i need to get to binding because my freet3 is low, has been low, and even though I'm still on low doses of NDT for the last 5 weeks, all of my labs changed except my FT3! Even my rT3 went down, but my free 3 is being stubborn. I need to have a chat with these binding proteins! 😜

I think what you want is to unbind the T3, so that your body can use it. But, it's not something you can consciously do. It just happens.

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