Why Only Checking TSH for Thyroid is Not Enough

If you live in Alberta and suspect that you have a thyroid issue but all the lab tests come back as “normal”, read on….

Alberta Health has recently implemented an algorithm for testing.  Think of those flow charts where one proceeds by answering “Yes” or “No” and then following the arrows to the next box with a yes/no question.  With regards to thyroid assessment, doctors are only allowed to do a screening thyroid check, i.e. TSH or Thyroid Stimulating Hormone.  If TSH is normal the thyroid is assumed to be normal and there is no further enquiry into the thyroid.  TSH is a measure of of how much the pituitary is trying to stimulate the thyroid to work harder, not an actual measurement of the thyroid itself.

This is problematic because normal levels or low normal levels of T4, the much less active thyroid hormone will create normal TSH readings (0.2 to 4.0 U/ml).  But if you had only T4 and no or very low T3, you would actually be in a hypothyroid state.

Why?  Like I state previously, T4 is much less active – it might take T4 10 times as long to perform the same function as T3, and thyroid hormones are all about metabolism. So if all your bodily processes take 10 times longer to complete, your metabolism will be very slow.  There are other issues with only checking TSH which will be covered in other posts.

And BTW – in the United States, the normal range for TSH is .2 to 3.0 U/ml.  This updated reference range has been in use for well over a decade, so our reference range is a bit behind the times.  If you follow the academic literature, optimal TSH may actually be lower for many conditions.

How would you ever know this is going on if it’s never tested?

If your doctor cannot fulfill your request for a more full thyroid assessment, then come see a Naturopathic Doctor.  We can and do order more extensive labs to help get to the root of the problem.

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