Many Md's treat by obsolete ranges, we have all (As Thyroid sufferers) been in normal ranges and suffered with symptoms, If you have those Free T3 and Free T4 levels with the ranges provided, we could give you more information. So please Post them if you wish.
Best Regards FTB4
His T3 and His T4 have been checked numerous times and they are always in range. Thank you for your information.
I found a graph of thyroid test reference ranges for children and adults. Here is the link.
http://en.wikipedia.org/wiki/Reference_ranges_for_blood_tests
I also found this. "For full term newborns, the range of normal TSH levels is quite large. TSH can vary between 1.3 and 16 microunits per milliliter of blood. After about a month, this range narrows to 0.9 to 7.7 microunits per milliliter, and by school age it decreases to 0.6 to 5.5 microunits per milliliter. This gradual decrease in TSH levels is normal, though levels of free thyroid hormone (T4) in the blood will remain relatively stable over the same time period.
Considerations
TSH level is only one test to assay thyroid function. It is often coupled with measurements of the thyroid hormones themselves, T3 and T4, or TSH releasing hormone (TRH). All these tests together can help a physician identify exactly where a problem occurs in a patient suffering from abnormal thyroid function tests. The methods for measurement of these different hormones are different however, and since TSH requires only a simple blood draw, it is often the first line lab test."
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In general, the answer is yes, the reference range is higher for young ones; however TSH is a pituitary hormone that is affected by so many variables that it is inadequate as the sole diagnostic for thyroid. At best it is an indicator to be considered along with more important indicators such as symptoms and also the levels of the biologically active thyroid hormones, Free T3 and Free T4.
Since symptoms are also hard to evaluate for young children, I think that he should be tested for Free T3 and Free T4. If the test results fall anywhere within the so-called "normal" ranges, the doctor will typically tell you that's adequate; however, that is frequently not the case. If those tests are in the low end of their reference ranges that is frequently consistent with being hypo. That is because the ranges are far too broad, since they have never been adjusted like was done for TSH over 8 years ago.
I have to emphasize that my opinions above are based on personal experience and knowledge about adult thyroid problems. I'm confident that it applies on a general basis, but you really need to discuss specifics with a good pediatric Endo that specializes in thyroid. Whether your current Endo fits that category or not is something you are going to have to determine as you follow up on this.
If you are concerned about his thyroid, request a Free T3 and Free T4, these tests are actual thyroid tests, TSH (Thyroid Stimulating Hormone) is a Pituitary Gland hormone.
The normal ranges for adults varies, the New ranges for TSH are .03 to 3.5 an older range many MD's use also is 0.5 to 5.5, Now this is for an adult, I don't know if the ranges are different in Pediatrics or infants in development. Free T3 is the acual hormone that the body needs to function, when the Pituitary senses a low Free T3, it sends a hormone (TSH) to the thyroid to make it produce more T4, then the body converts it to Free T3, so the less hormone the thyroid secretes, the higher the TSH and the more the thyroid secretes, the lower the TSH, The more precise test would be The Free T3 and Free T4 tests . If you get these tests done, you can post the results with the reference ranges provided for each, then we can give you more information. Best Regards FTB4