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My TSH and T4 levels were fine. So if they were in the range, I do not need to be concerned about this T3 number? I have hypothyroid and hashimotos disease. My medicine constantly needs to be adjusted. My TSH is not the best guide for this. So, my doctor actually uses Free T4 and Free T3 to get the most information.
I appreciate your recommendation. It sounds like she accidently ordered the wrong test. However, now that I have an equalibrium dialysis measurement of T3 and it is out of the range, I will still be charged $45 by you for your response. I do not think that your answer of "you don't need to be concerned about you T3 number" is a detailed enough answer to warrant this amount of money. Please provide me more information regarding this type of thyroid test and what causes the thyroid to go below the normal range on this type of lab test. I am well educated and would like a detailed answer for this type of payment even if I have no reason to be concerned.
most circulating T3 is bound to plasma proteins, like thyroxine binding protein. only about 0.3% exists in the free, unbound state and is available for ex-change with intracellular T3 receptors. when an increase in circulating thyroxine binding protein is suspected as the cause of an elevated total T3 level, the free T3 assay can differentiate this condition from true hyperthyroidism. with a measurement of free T3 with equilibrium dialysis, radioimmunoassay (RIA), you also need a thyroxine binding protein level as well to understand the whole picture. so your very very low free T3 level is normal since only about 0.3% of the total T3 is free. does this make sense?
It makes sense in the way you described it. However, if that is the case, then why wouldn't the standard ranges be different to reflect this?
If my thyroxine binding protein levels were normal or low and my T3 levels were as I reported on these labs, is there any other information that you would you could provide based on that information.
So, just to summarize: If your free T3 is extremely low and your thyroxine binding protein levels are normal or low, there is no cause for concern. This is completely normal. This lab test showing that these free T3 scores are completely out of the range are unimportant and should be disregarded.
If this is true, can you please tell me in which case this test is supposed to intentionally be ordered and the results should be paid attention to.